These recommendations are for people at average risk for certain cancers. Talk to a doctor about which tests you might need and the screening schedule that’s right for you. It’s a good idea to also talk about risk factors, such as lifestyle behaviors and family history that may put you or your loved one at higher risk. See more in-depth recommendations in Cancer Screening Guidelines by Age.
Age 25–39 Screening recommendations
Cervical cancer screening recommended for people with a cervix beginning at age 25.
Age 40–49 Screening recommendations
Breast cancer screening recommended beginning at age 45, with the option to begin at age 40.
Cervical cancer screening recommended for people with a cervix.
Colorectal cancer screening recommended for everyone beginning at age 45.
At age 45, African Americans should discuss prostate cancer screening with a doctor.
Age 50+ Screening recommendations
Breast cancer screening recommended.
Cervical cancer screening recommended.
Colorectal cancer screening recommended.
People who currently smoke or formerly smoked should discuss lung cancer screening with a doctor.
Discussing prostate cancer screening with a doctor recommended.
Advances in genomic technology are paving the way for blood based cancer screening – but is it better?
Research conducted by Epic Health Research Network revealed a drop between 86-94 percent in preventive cancer screenings for cervical, colon, and breast cancer performed nationwide compared with equivalent weeks from 2017 to 2019.1 The decline in screening in the wake of the COVID-19 pandemic can be in part attributed to patients’ hesitation to visit health centers and other complications of the pandemic, but the statistics are concerning.
Cancer screening seeks to identify cancer in people before they have any symptoms when it may be easier to treat, and regular screening plays an important role in avoiding difficult and costly treatment and, in many cases, saves lives. Guidelines have been developed around screening for some cancers, including breast, cervical, colorectal, endometrial, lung, and prostate cancer, but there are many cancer types for which there are no current effective screening tools or guidelines.2
While the benefits of screening are clear, there are barriers to regular screening for many, ranging from fear or hesitancy to undergo invasive screening tests, like colonoscopy, to difficulties accessing care or not having the flexibility to take time off work. Scientists and physicians continue to strive toward developing more accurate screening tools that will improve compliance rates and make screening easier and more accessible.
“We’ve been working for decades now to understand how to identify cancers early before they’ve had a chance to spread,” says Kevin Schulman MD, MBA, Professor of Medicine at Stanford University. “Especially for solid tumor cancers like breast cancer or colon cancer, which, if found early, can often be treated effectively, there’s significant opportunity in early detection.”
Improving screening technology and broadening the scope of screening to include additional cancer types is the ongoing goal of screening research. “If a better screening test was available that would help us detect the disease even earlier and would be less of a burden for patients—less invasive or time consuming, for example—that could be a real benefit,” Dr. Schulman says.
Hope on the Horizon? – Blood Tests for Cancer Screening
Against the backdrop of challenge and opportunity in cancer screening, new blood tests that can detect cancer in early stages, often before a person has any symptoms, are an exciting development.
Blood tests to screen for cancer are not new. Hematologic cancers, like lymphoma and leukemia, are often first identified through a blood test (and confirmed by additional diagnostic tools), and the PSA (prostate-specific antigen) test is a blood test used to screen for prostate cancer.
This new category of screening test is different in that it uses genomic technology developed to identify circulating pieces of solid cancer tumor DNA, or ctDNA, in the bloodstream. To date, these tests have been used to provide genetic information about tumors in patients already diagnosed with cancer, which can help guide treatment decisions and monitor the effectiveness of specific therapies. Now, blood tests developed to screen for cancer, are building on that genomic technology to detect early-stage cancer before a patient experiences any symptoms.
Two Screening Tests to Watch
Galleri by GRAIL
Galleri™ is a multi-cancer early detection (MCED) test, developed by GRAIL. An MCED test detects and localizes small amounts of circulating tumor signal in the blood and can detect many cancer types through one blood draw. Josh Ofman, MD, Chief Medical Officer and Head of External Affairs at GRAIL, says, “Galleri is a first-of-its-kind, multi-cancer early detection (MCED) blood test, capable of detecting more than 50 types of cancer—45 of which lack recommended screenings today.”
The Galleri test is intended for use in those with an “elevated risk of cancer,” which, Dr. Ofman says, includes those 50 and older who don’t have any symptoms. Galleri was developed as “a complement to existing annual single cancer screening tests such as mammograms and colonoscopies. Galleri has not been demonstrated to be as sensitive as mammograms and colonoscopy for detecting early stage cancers so these routine screening tests should not be omitted as part of an individuals overall health maintenance and wellness strategy.
The test is available to patients through a prescription from a provider. After a blood sample is collected, it is processed in GRAIL’s lab, and results are delivered to the ordering healthcare provider within 10 business days.
If results indicate a “cancer signal detected” result, Dr. Ofman says, “in most cases, the Galleri test report provides predicted cancer signal localization, indicating where in the body the cancer is located, which helps physicians determine the appropriate diagnostic workup.” For patients who receive a “no cancer signal detected” result, Dr. Ofman says, the test report will remind individuals to continue with their standard-of-care cancer screenings.
A paper published in Annals of Oncology revealed final study results of the Circulating Cell-free Genome Atlas (CCGA) study investigating the performance of the Galleri test.3 The paper reported that “in 2,823 people already diagnosed with cancer and 1,254 people without cancer, [the Galleri test] detected cancer signals from more than 50 different types of cancer and found that across all four cancer stages (I, II, III, IV), the test correctly identified when cancer was present (the sensitivity or true positive rate) in 51.5 percent of cases. The test’s specificity (the true negative rate) was 99.5 percent, meaning that the test wrongly detected cancer (the false positive rate) in only 0.5 percent of cases.”
The fact that the sensitivity of the Galleri test identifies the presence of ctDNA of cancers that up to now we have not been able to screen for is a significant advance. The sensitivity of the test varied across tumor types, the paper’s authors noted. “In solid tumors that do not have any screening options, such as esophageal, liver and pancreatic cancers, overall sensitivity of the test was twice that for solid tumors that do have screening options, such as breast, bowel, cervical and prostate cancers: 65.6 percent compared to 33.7 percent. Overall sensitivity in cancers of the blood, such as lymphoma and myeloma, was 55.1 percent.”4
The Galleri test is available now to patients in the US. Galleri requires a prescription and can only be ordered by a licensed healthcare provider. GRAIL plans to seek FDA approval for Galleri following its initial introduction as a Laboratory Developed Test (LDT). “Introducing Galleri as an LDT enables us to get this transformative technology that’s in our hands today into the hands of doctors and their patients, while we pursue FDA approval,” Ofman said.
GRAIL received Breakthrough Device Designation from the FDA and are in ongoing conversations with the agency. The GRAIL laboratory is CLIA certified (Clinical Laboratory Improvement Amendments) and CAP-accredited (College of American Pathologists).
LUNAR-2 by Guardant Health
The LUNAR-2 assay is another blood test for cancer screening showing promise. LUNAR-2 is a liquid biopsy being developed by Guardant Health to detect colorectal cancer (CRC) in an average-risk adult population.
Kathryn Lang, MD, vice president of Health Outcomes and Evidence at Guardant Health, says the LUNAR-2 assay reflects the widespread momentum behind utilizing genomic technology to propel screening and increase early detection. “There is an awful lot of push right now to bring much more advanced testing to the field of screening; it’s really exploding right now.”
Guardant Health has already developed and gained FDA approval of a liquid biopsy test (Guardant360® CDx) for advanced-stage cancer patients, which help doctors recommend targeted therapies based on the unique mutations of a tumor. The company also recently introduced a new test (Guardant Reveal™), which can detect signs of residual cancer in early-stage colorectal cancer patients.
Dr. Lang notes that LUNAR-2 builds on this technology. “The current testing technology requires some development to catch cancer earlier because the signal in early-stage cancers is not as strong—there’s just less cancer there, so the test requires a bit more refinement to be useful as a screening tool.”
That refinement is reflected in what Dr. Lang says is a “multi-modal” test. “The LUNAR-2 assay detects markers of cancer in three different areas of the genome,” she notes. “We’re looking for the building blocks, or the language of the cancer that we can find, but for this test we have to add some things on to look for the earliest stage cancer: the methylation marker, or the extra signals on those building blocks of the of DNA that can be associated with cancer, and wherein the actual DNA certain proteins are positioned, which can also be highly correlated with cancer.”
While the genomic technology can sound complicated, Dr. Lang says, “the LUNAR-2 assay has been designed to return a result that denotes simply ‘present’ or ‘absent,’” meaning that markers of colorectal cancer are present in a patient’s blood or are not present.
If the screening test result reflects “present,” a patient would be guided by their physician to undergo a diagnostic procedure or test, which in this case will be a colonoscopy. This distinction between a “screening” test and a “diagnostic” test is significant, she notes, because while the screening test can be a good indicator, a patient would still need to seek further testing to confirm the result and receive a final diagnosis.
The Guardant Health test is being developed for “average risk” patients, which Dr. Lang says would be defined as “somebody 45 or older who has absolutely no symptoms of colorectal cancer—no changes in bowel habits, no weight loss, no bleeding or other symptoms—and has no first-degree relatives who have had CRC or any other high-risk features like a familial predisposition or any conditions, like inflammatory bowel disease. If none of those are present, then you are average risk, and these tests are being developed for those average-risk individuals.”
In data presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, Guardant Health reported that the LUNAR-2 assay achieved overall sensitivity of 91 percent in early-stage CRC (Stage I, II, and III), and specificity of 94 percent.5 In a press release highlighting the data, Guardant Health also noted that “no differences in sensitivity for CRC detection were observed in patients presenting with asymptomatic disease, compared to those patients who were symptomatic, despite the lower cell-free DNA (cfDNA) tumor fractions observed in asymptomatic patients, suggesting the test will have clinically meaningful performance in an average-risk screening population.”6
Anemia and fatigue are a common complication of Polycythemia and Myelofibrosis; understand treatment-what can you do about it?
The LUNAR-2 test is currently being evaluated through the ECLIPSE trial, a 10,000 patient registrational study, and results are expected in 2022. From there, the test will need to go through the FDA-approval process. “The FDA process takes about 12 to 18 months,” Dr. Lang says. “We’re setting a very high bar for ourselves, and we expect to be going through a very significant process to prove that this is safe and valuable to patients.
Potential Complications and Considerations for Patients and Providers
While the Galleri and LUNAR-2 tests reflect the promise of blood tests as screening tools, there are notable issues related to early-stage screening tests and the roll-out among patients and providers.
“A potential complication of tests developed to detect cancer at very early stages is that a blood test may detect signs of cancer that our immune system would have eliminated on its own before it progressed to a state that requires treatment,” Dr. Schulman says. “This has been a real challenge in screening for prostate cancer, for instance. Many men will develop early-stage prostate cancer, but very few will die from it. We’ve gotten a little bit more cautious about how we screen for prostate cancer as a result.”
Dr. Lang notes that in the case of the LUNAR-2 assay, designed to screen for colorectal cancer, “there is a huge body of evidence that if the signal [for colorectal cancer] is detected, that colorectal cancer does not disappear on its own and does require treatment.” But, she adds, this isn’t the case for all cancer types. “Not all cancers are created equal, but for CRC, early detection is critical as treatment of early-stage colorectal cancer can be effective. The five-year survival rate for CRC is excellent—about 95 percent.”
Another issue for patients to consider is the potential for these highly sensitive tests to generate false positives, which may lead to invasive diagnostic tests, and false negatives, which would mean a cancer was present that wasn’t detected.
“We have seen the impact of false positives from highly sensitive tests in the high-resolution CT scans administered to cigarette smokers that we screen for lung cancer,” Dr. Schulman says. “These tests find a lot of cancers but have a high false positive rate—about 20 percent.” For patients who get a false positive, the diagnostic testing and follow-up that comes next can be a significant burden, physically, emotionally, and financially. “The worst test is one that leads to lots of people getting scared and getting a very involved workup.”
Another issue is that these tests may not be as sensitive as routine mammography or colonoscopy. The earlier the cancer the greater the possibility that a test can produce a false negative result. Blood tests should not be used to replace these existing screening programs.
So while the idea of early screening and the potential for significant benefit to patients is exciting, Dr. Schulman urges caution. “There’s this challenge to make sure we’re finding things that really will progress and not things that won’t progress, and that’s very hard. It’s still really early, and there’s a lot we still need to understand about these tests.”
In the case of the Galleri test, the most-recent study results report false positives in only 0.5 percent of cases, which is very low compared with other screening tools that exist today, but patients should always discuss this aspect of screening tests with their provider in advance.7
Ted Snelgrove, CEO of Curve Biosciences, has spent more than 25 years in the field of molecular diagnostics and personalized medicine and says that it’s important for patients considering these tests to understand the balance of specificity and sensitivity built into the design.
“In building algorithms that translate raw genomic data into clinical test results, computational biologists can weight the math to optimize the natural tradeoffs between sensitivity and specificity,” he says. “If it’s designed to be more sensitive, it picks up more tumors, but it will likely be at the expense of lower specificity (more false positives).” These limits are inherent to the underlying technologies that quantify ctDNA from bodily fluids, and individual tests may require different algorithms to reflect context-driven priorities for assessing risk.
Being able to understand this feature of test design and articulate the issue to patients is something that providers will need to become comfortable with as tests become more widely available. “This is critical for ordering physicians because they have to know how to frame alternatives when they get results back as positive or negative and be able to explain the levels of confidence for any results that are presented to patients,” Snelgrove says.
In fact, providers will face a range of challenges as liquid biopsies are introduced as screening tools. Continuing education will become essential across health systems that adopt these tests to ensure providers can offer clear information and guidance. In some ways, the testing technology is emerging faster than the rest of medicine is evolving, so providers will need to be trained so they are confident they can process and act on the insights these tests can generate.
Snelgrove says, “Primary care doctors and internists will need to get up to speed on how to manage these tests—ordering and explaining the results and helping patients understand how this can affect their plans once results are in.” Not all providers have training in genomic technologies or biostatistics, and there will be a steep learning curve over the next decade.
Health systems and insurers will also need to create appropriate guidelines for patients to benefit from the tests. “I liken this in some ways to the Tesla story,” he says. “They developed this novel technology for building electronic vehicles, but the macro-challenge has been creating the battery-charging infrastructure that is now being deployed across the country so the cars can be practical to own and operate. In the same way, these novel genomic tests are like the electronic car, so now we need to devise and scale the decision support systems in medicine to manage routine cancer screening for people who are otherwise asymptomatic.”
A Pivotal Moment in Cancer Screening
Ultimately, blood tests developed for cancer screening present an opportunity for more cancers to be identified early when they are more treatable.
“Cancer is expected to become the leading cause of death in the US this year, in large part because the majority of cancers are found too late when outcomes are poor,” Dr. Ofman says. “Recommended screening tests save lives, but only cover five cancer types in the US. In fact, 71 percent of cancer deaths in the US have no recommended early detection screening.”
The ability of the Galleri test to detect cancer without existing screening guidelines has the potential to provide significant benefit. “Finding cancer early, when treatment is more likely to be successful, is one of the most significant opportunities we have to reduce the burden of cancer. If used at scale alongside existing screening tests, the Galleri test could have a profound impact on how cancer is detected and, ultimately, on public health,” Dr. Ofman says.
In the case of the LUNAR-2 assay, which is being developed as a first-line screening test for CRC, Dr. Lang says, “We believe it’s important to expand first-line screening because to get to the best outcomes possible in the US we need to get to a compliance or screening level of those eligible of about 80 percent.” Right now, she notes, “the Centers for Disease Control and Prevention (CDC) says we’ve maxed out at about 65- 69 percent (and that’s not equal across the U S—certain states are a lot less than that and certain states are a lot higher).”
LUNAR-2, which can be performed in a doctor’s office, has the potential to remove two key barriers to CRC screening. It can be completed during an office visit, which means patients don’t have to go to a separate appointment at a different facility; and, it’s non-invasive. “A first-line test performed in the office would allow us to get a lot more people tested, which is really the promise of blood-based colorectal cancer screening,” Dr. Lang says.
Looking Ahead
As with all decisions you make about your health, a decision to move forward with any screening should be informed and made in consultation with your healthcare provider.
“If patients want to go forward with a blood test for cancer screening,” says Dr. Schulman, “it’s important to understand the risks, which could include finding a false positive or a false negative. And, unfortunately, patients also need to be aware that though they’re taking a screening test meant to identify early-stage cancer, there’s no guarantee that they won’t learn they have a later-stage cancer, one that can’t be as easily treated.”
As the Guardant Health tests and others continue through development and testing phases, Dr. Lang says, the most important thing patients should takeaway is the importance of screening overall. “It’s incredibly important to get screened. Don’t put off screening today because you’re waiting for a blood test; make your screening appointment now and know we’re working hard to provide more screening options in the future—for CRC and other cancer types.”
You may have heard that mammograms, the tests that are commonly used to detect breast cancer, can actually increase the risk cancer. Well, you’re not wrong! Yet, these breast screenings are considered to be the most effective form of detecting breast cancer, at least according to the Center For Disease Control (CDC).
There’s actually an overwhelming amount of research that proves mammograms can have a negative impact on your health and can even result in misdiagnoses. Staying on top of breast health is still important, but how can you avoid mammograms? Thankfully, there are numerous safe alternatives to this method of breast screening.
Why Mammograms May Threaten Your Health
If you get mammograms periodically, I would highly advise you consider alternative means of testing for breast cancer. There are numerous studies that suggest mammograms can not only be ineffective at identifying cancer, but are harmful to your health as well. To start, let’s look at the studies that test the effectiveness of mammograms for identifying cancer.
One of the biggest issues with mammograms is over-diagnosis and, as a result, over-treatment. A National Cancer Institute commissioned an expert panel that concluded that “early stage cancers” are not cancer, they are benign or indolent growths. This means that millions of women were wrongly diagnosed with breast cancer over the past few decades and have been subject to harmful treatment, when they would have been better off leaving it untreated or diagnosed; frighteningly, it is not uncommon for a breast cancer misdiagnosis to occur.
Another study that was recently published in the British Medical Journal concluded that regular mammogram screenings do not reduce breast cancer death rates. The researchers found no evidence to suggest that mammograms are more effective than personal breast exams at detecting cancer in the designated age group. The study involved 90, 000 Canadian women and compared breast cancer incidence and mortality up to 25 years in women aged 40-59 (source).
22% of screenings detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial. The doctors explained: “This means that 106 of the 44,925 healthy women in the screening group were diagnosed with and treated for breast cancer unnecessarily, which resulted in needless surgical interventions, radiotherapy, chemotherapy, or some combination of these therapies.”
In a 2009 Cochrane Database Systematic Review of breast cancer screening and mammographs, the authors concluded, “Screening led to 30 percent overdiagnosis and overtreatment, or an absolute risk increase of 0.5 percent. This means that for every 2000 women screened for 10 years, one will have her life prolonged, and 10 healthy women who would not have been diagnosed if they had not been screened, will be treated unnecessarily.”
Perhaps the most notable information was provided by the Swiss Medical Board, an independent health technology assessment initiative. The board was asked to create an unbiased review of mammography screening. The board comprises a medical ethicist, a clinical epidemiologist, a pharmacologist, an oncologic surgeon, a nurse scientist, a lawyer, and a health economist.
The Swiss Medical Board reported that for every breast-cancer death prevented in U.S. women over a 10-year course of annual screening starting at age 50:
490-670 women will likely have a false positive mammogram with repeat examination
70-100 will likely have an unnecessary biopsy
3-14 will likely be over-diagnosed with a breast cancer that would never have become clinically apparent
Given the overwhelming amount of research showing the ineffectiveness of mammograms, the board recommended completely abolishing mammogram screenings. In addition, approximately 50 percent of women have dense breast tissue, meaning that it’s difficult for mammographs to even process. Both dense breast tissue and cancer appear white on an X-ray, thus it’s extremely difficult and practically impossible for a doctor to detect cancer with this type of tissue (source).
Mammograms are not only often ineffective, but they could do more harm than good as well. A study published in the British Medical Journal in 2012 proved that women carrying the BRCA 1/2 mutation are extremelysusceptible to developing radiation-induced cancer, meaning that mammograms are much more harmful to them. Women with this mutated gene who were exposed to diagnostic radiation before the age of 30 were found to be twice as likely to develop breast cancer in comparison to women without that mutation.
The study also found that the radiation-induced cancer was dose-responsive; in other words, the higher the dosage, the greater their risk of developing cancer. The authors stated, “The results of this study support the use of non-ionizing radiation imaging techniques (such as magnetic resonance imaging) as the main tool for surveillance in young women with BRCA 1/2 mutations.”
Even though this research suggests women with this mutated gene shouldn’t have a mammogram annually, since it can literally double their risk of developing breast cancer, the National Cancer Institute still suggests that they continue to do so starting at the age of 25.
Another study in the British Medical Journal from December 2011 questioned whether or not breast cancer screenings did more harm than good, and as it turns out, it does more harm indeed!
So you can get a clear picture, you can get as much radiation from one mammogram screening as you could from 1,000 chest X-rays. Mammograms also tightly compress your breasts, which can result in a greater spread of cancerous cells if they already exist at the time of the test. Dr. Samuel Epstein, one of the world’s top cancer experts, said: “The premenopausal breast is highly sensitive to radiation, each 1 rad exposure increasing breast cancer risk by about 1 percent, with a cumulative 10 percent increased risk for each breast over a decade’s screening.”
USA Today reported on a new breast screening technology, 3-D mammography, which is said to double the amount of radiation exposure. The article explains, “Radiation is a known cause of breast cancer. Researchers in recent years have become concerned about radiation exposure from medical imaging, particularly CT scans. A 2009 analysis estimated that CT scans cause about 29,000 cancers and 14,500 deaths a year.”
The following video is taken from The Truth About Cancer, in which Ty Bollinger interviews Dr. Ben Johnson on the correlation between mammograms and breast cancer:
Alternatives to Mammograms for Cancer Screening:
If you’ve already had a mammogram or multiple in your life, don’t stress too much! If you’re concerned about the radiation associated with the testing, there are numerous other alternatives to test for breast cancer that are just as effective, if not more.
Dr. Ben Johnson suggests, “Well there’s two better options. If you’ve got a lump, if you think you’ve got something, ultrasound is great. It’s a test of anatomy… But if you’re looking about prevention, if you’re talking about screening, there’s really only one device out there and that is thermography. An infrared thermal camera. Nothing touches the lady. Nothing smashes her breasts. There’s no cancer causing radiation.”
He continues to say, “So, that would be like an ultrasound because they can see the lump, they can see its consistency. They can see where there’s calcium in it. And they can look at blood flow because tumors are going to have increased blood flow. So, for instance, a sensitivity of ultrasound is up around 80%. It’s much higher than mammograms. And the sensitivity is higher too.”
Thermography is highly recommended as an alternative breast cancer test as it’s non-invasive and can even detect tumour activity years before a mammogram could. A 2008 study published in the American Journal of Surgery stated that breast thermography has a 97% “sensitivity rating” for finding malignancies before a visible tumour has been formed. Contact the American College of Clinical Thermography for more information.
Another alternative is the ONCObolt, which was designed by Purdue University researchers Dr. Dorothy and Dr. James Morré. ONCObolt tests for the universal cancer cell marker ENOX2 and can also identify the specific origin of cancer cells in the bloodstream. ONCOblot is has an astonishing 99% accuracy rate for discovering tumours when they are tinier than a pinhead. To learn more, check out the Oncoblot website or talk to a health professional.
To be clear, I am not a doctor. I am simply someone who is extremely passionate about exposing the cancer industry and providing people with safe alternatives to conventional testing and treatment. It’s crucial that we spread awareness about this topic, because so many of the conventional methods or diagnosis and treatment cause cancer including the tests and treatments involving radiation and especially chemotherapy. When we open up the dialogue to actually suggest better methods of testing and treatment, we promote positive change, and at the very least, educate one another.
If you have any questions about this article or about conventional treatments, please feel free to reach out to me, but I would also strongly advise consulting with your doctor, preferably a naturopath!
What do these ‘awareness raising’ efforts have in common? They almost all funnel the miseducated masses into fear-driven screening programs that promise to ‘save lives’ by ‘detecting disease early’ instead of focusing on removing and/or lessening the preventable causes of disease. Why not employ real prevention and focus on root cause resolution, which is to say, dietary changes, detoxification, and various modifiable lifestyle factors such as stress reduction — none of which, incidentally, require pharmaceutical intervention. In the case of cancer, the primary focus should be on removing exposure to cancer-causing agents (carcinogens).
But cancer awareness raising campaigns intentionally avoid the term “carcinogen,” as removal of these primary drivers were an irrelevant consideration. The problem is that conventional treatments like chemotherapy and radiation are themselves carcinogenic, and should be avoided in principle by anyone looking to prevent, treat and/or reverse cancer, undermining the cancer industry’s main cash cow for the past half century. Additionally, if you focus on identifying and removing the cause, you can’t get people to throw billions of dollars into fund-raising campaigns by promising a cure that only exists as a possibility in the future, and requires ceaseless cash offerings and supplication to the biotech, pharmaceutical and medical ‘Gods.’
So, have these disease campaigns met their promises?
This all important question is now drawing widespread attention following the publication of study in the International Journal of Epidemiology titled: “Does screening for disease save lives in asymptomatic adults? Systematic review of meta-analyses and randomized trials.”1
As many of our readers who follow our work are already aware, routine mass screening for cancer in healthy populations commonly leads to overdiagnosis (finding lesions that do not cause harm or death), and when not identified as such, overtreatment (a euphemism to what amounts to succumbing to medical abuse).
Overdiagnosis is exceedingly common primarily because of mistakes in cancer classification based on a fundamental, at least half century old misunderstanding of cancer biology. In 2013 the National Cancer Institute commissioned an expert working group to look at present day definitions of screen detected cancers such as ductal carcinoma in situ (DCIS) (‘breast cancer’), high grade intraepithelial neoplasia (HGPIN) (‘prostate cancer’) and thyroid papillary carcinoma (thyroid ‘cancer’), with the shocking conclusion that these should be reclassified as non-cancerous, benign growths of epithelial origin. Yes, after millions in the U.S. over the past few decades had their breasts, prostates, ovaries, and thyroids removed as a ‘precautionary’ approach, now they are being told they never had cancer to begin with. In other words, they had abnormal tissue growth that would never have progressed to cause harm or death. But these non-malignant lesions or tumors were treated as if they were life-threatening cancers anyway, with patients often losing their breasts or prostates as a result of medical errors that were disingenuously recorded in cancer statistics as ‘life saving’ interventions that ‘detected cancer early,’ resulting in inflating the ‘5-year survival’ rates in a way that appears to show medical progress. These semantical and statistical misrepresentations, are why, absurdly, thecancer industry can announce that they saved over a million lives in the past few decades, when in fact quite the opposite may be true.
As summarized on Science Daily, the new study confirms that despite screening programs picking up millions of new ‘early cancer’ diagnoses disease-specific mortality has not declined significantly as would be expected if these ‘cancers’ were actually non-benign or life threatening”:
“Screening for disease is a key component of modern healthcare. Yet, new surprising new research shows that few currently available screening tests for major diseases where death is a common outcome have documented reductions in disease-specific mortality. Evidence was evaluated on 16 screening tests for 9 major diseases where mortality is a common outcome. The researchers found 45 randomized controlled trials and 98 meta-analyses that evaluated disease-specific or all-cause mortality. Reductions in disease-specific mortality were uncommon and reductions in all-cause mortality were very uncommon.”
Many in the U.S. are still not aware that breast screening for women aged 40-49 and PSA-based prostate screening in healthy men lost their endorsement in 2009 and 2012, respectively, by the U.S. Preventive Task Force (USPSTF), explicitly because of concerns that the psychological and physical harms of overdiagnosis and overtreatment outweighed their benefits in reducing cancer specific mortality. In fact, prostate screening was associated with increased mortality! Although not discussed by the USPSTF, we have detailed the many ways which which mammography is likely increasing mortality in those undergoing them.
According to Science Daily, senior author of the new study, professor John Ioannidis stated:
“Our comprehensive overview shows that documented reductions in disease-specific mortality in randomized trials of screening for major diseases are uncommon. Reductions in all-cause mortality are even more uncommon. This overview offers researchers, policy-makers, and health care providers a synthesis of RCT evidence on the potential benefits of screening and we hope that it is timely in the wake of recent controversies.”[emphasis added]
There are vast resources of energy, money, and time put into screening programs. This new meta-analysis should put a pause in the ongoing push to have asymptomatic people subject themselves to unnecessary screening. But the truth is that only we can make these decisions for ourselves. The medical-industrial complex will likely continue to push for these programs regardless of the evidence against them, and the governmental agencies in charge of overseeing them will likely continue to default to a cheerleading instead of regulatory role. We can only hope that our readers continue to educate themselves and make a fully informed choice.
Article References
[1] Nazmus Saquib, Juliann Saquib, and John Ioannidis. Does screening for disease save lives in asymptomatic adults? Systematic review of meta-analyses and randomized trials. International Journal of Epidemiology, 2015 DOI: 10.1093/ije/dyu140
When it comes to using mammograms as a tool to screen women for breast cancer, how do you define success? At a minimum, you’d want to know that women who get mammograms are less likely to die of breast cancer than women who didn’t get the tests.
So the big Canadian study published last week in the British Medical Journal was rather inconvenient for the die-hard fans of mammography. The study sorted nearly 90,000 women into two groups. About half of them had mammograms, and the other half didn’t. Those who had the screening tests were more likely to be diagnosed with breast cancer.
You might expect this to be useful, by catching cancers at an earlier, more treatable stage. But it didn’t turn out that way. After tracking these women for up to 25 years, the researchers found that women who had mammograms succumbed to breast cancer at the same rate as women who didn’t get the tests.
The American College of Radiology – the medical group that represents the doctors who read mammograms – pounced on the study right away. In a statement, the ACR called the study “incredibly flawed and misleading.” Taking its results seriously “would place a great many women at increased risk of dying unnecessarily from breast cancer,” it warned.
As my colleague Monte Morin reported, the authors of the study said they stood by their results. But the accusations from high-profile radiologists have kept coming.
Now an expert on preventive medicine and screening is fighting back. In an opinion essay published online Wednesday on CNN.com, Dr. H. Gilbert Welch of the Dartmouth Institute for Health Policy and Clinical Practice explains why the ACR’s two main arguments against the Canadian National Breast Screening Study study are wrong.
First, the radiology group claimed the Canadian results could not be trusted because the women were screened with “second-hand mammography machines” that were operated by technologists who “were not taught proper positioning,” producing sub-par breast films read by radiologists who “had no specific training in mammographic interpretation.”
Welch sums up the ACR critique like this: “Canada is a Third World country.” Not only is this not true, he writes, it’s disingenuous. That’s because the clinical trials that radiologists cite in favor of mammography are even older than the Canadian study. “In fact, one of the trials most favorable to screening – the Health Insurance Plan of New York’s – dates from two decades before Canada’s, in the early 1960s, when mammography technologies were primitive,” Welch writes.
The ACR’s other complaint is that the Canadian trial stacked the odds against mammography by assigning women with “large incurable cancers” to the group that got the mammograms. “This guaranteed more deaths among the screened women than the control women,” according to the ACR statement.
Once again, Welch isn’t buying it. Critics have made this allegation before, and it’s so serious that Canada’s National Cancer Institute initiated a two-year investigation. As reported in the Canadian Medical Assn. Journal in 1997, the investigators “found no evidence of a deliberate attempt to conceal the alterations.”
Nor is there any evidence of cheating in the data, Welch explains. If the Canadian researchers were shunting the sickest patients into the mammogram group, then there were would be more deaths among women who had mammograms than among women who didn’t. But there weren’t. “The rate of death in the two groups was exactly the same, every year, for 25 years,” Welch writes.
Welch has coauthored many studies about mammography, and he says there’s a good explanation for why mammograms don’t seem to be helpful as a screening tool: the tests find “small, unimportant” abnormalities that are labeled “cancer” but are “not destined to cause them any problems,” he writes. (Also, better treatments have erased much of the advantage of finding cancers early.)
Though some radiologists have accepted the growing evidence that screening mammography is flawed, members of the “old guard” are still quick to attack the studies that don’t fit their worldview, Welch writes. He has some advice for those people: Grow up.
“It’s time to stop the unfounded allegations,” Welch writes on CNN. “It might be standard procedure for politics but not for science. Too much energy has been devoted to discrediting the Canadian study and not enough to understanding it.”
A variant in a gene involved with inflammation and the immune response is linked with a decreased risk of lung cancer. That is the finding of an analysis published early online in CANCER, a peer-reviewed journal of the American Cancer Society. The results add to the growing body of literature implicating these processes in the development of lung cancer.
Meredith Shiels, PhD, MHS and Anil Chaturvedi, PhD, of the National Cancer Institute in Rockville, MD, and their colleagues analyzed 1,429 variants in inflammation- and immunity-related genes from 378 patients with lung cancer and 450 healthy controls from the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial. The investigators observed a significant link between lung cancer and 81 single nucleotide polymorphisms (SNPs) located in 44 genes.
They then compared these results with observed or imputed data from four recently completed genome-wide association studies (GWAS) that included 5,739 lung cancer cases and 5,848 controls. Of the 81 SNPs, one in particular — named rs4648127 and located within the NFKB1 gene — was associated with lung cancer in both analyses. This SNP was linked with an estimated 44 percent reduced risk of lung cancer in the cancer screening trial and a 21 percent reduced risk in the combined GWAS analysis.
The NF-κB, or nuclear factor kappa B, protein that is produced in part from the NFKB1 gene is known to play an important role in immunity and inflammation by regulating gene expression, cell death, and cell proliferation. Also, previous research has shown that immunity and inflammation may affect the development of lung cancer. “Our study provides further evidence that inflammation may be associated with lung cancer risk,” said Dr. Shiels. She added that future studies should further examine the NFKB1 gene and its relationship with lung cancer risk.
Randomized clinical trials are widely acknowledged as the best way to determine whether a cancer screening test saves lives. But even when trial results indicate that a particular screening method has a clear benefit, the findings may not be easily translated into recommendations for the public. The results of a screening trial may apply only to certain people, and the findings can change as the study period lengthens—all of which means that the results may not apply to the general population.
For example, the National Lung Screening Trial (NLST) showed that screening of current or former heavy smokers with three annual low-dose spiral CT scans can reduce their risk of dying from lung cancer. But NLST enrolled only people aged 55 to 74 who had smoked for 30 pack years and had quit less than 15 years previously.
“Would a similar screening regimen also benefit younger or older smokers? Would lighter smokers benefit equally? And when should they start and stop screening?” asked Dr. Eric “Rocky” Feuer, scientific coordinator of NCI’s Cancer Intervention and Surveillance Modeling Network (CISNET). Patients and doctors alike will almost certainly ask these questions.
CISNET’s five research teams use modeling to try to answer these types of questions for several different cancer types. Using the results of screening trials, the teams are trying to estimate the true benefit of screening in the general population and to identify the optimal way to implement screening within the health care system.
The teams’ extremely complex computer programs, which for some cancer types (such as breast and colorectal) have been used and constantly refined for over a decade, incorporate a wide variety of information. This information includes not only trial data but observational data, epidemiologic data, and information on the natural history of each cancer type.
One of CISNET’s original mandates was to tease out the role that screening has played in the observed decline in deaths from some cancer types over the last few decades. In a landmark 2005 paper in the New England Journal of Medicine, CISNET researchers determined that screening mammography likely accounted for half of the 24 percent decrease in breast cancer mortality that was observed between 1989 and 2000.
A major goal of the CISNET lung cancer team is to “integrate the NLST results into general practice,” said Dr. Pamela McMahon of Massachusetts General Hospital, the principal investigator of the lung cancer team, which also includes researchers from five other universities. “We have to extrapolate from the limited scenario of the NLST, because that [trial] doesn’t match the population experience.” (See “After Landmark Study, Exploring Questions about Lung Cancer Screening.”)
“We’re looking at every permutation you can think of: ages to start screening, ages to stop screening, how many pack years [smoked], how many years since quitting, how frequently to do the screens,” said Dr. McMahon.
Once the results are complete, the researchers hope to use them to create an interactive projection tool that will let policy makers see how implementations of different lung cancer screening programs in their community would alter lung cancer mortality, similar to the mortality projection tool produced by the CISNET colorectal cancer team.
Two Enormous Trials, Two Different Results
The three research groups in the CISNET prostate cancer team are tackling an equally ambitious, although entirely different problem. Two large randomized clinical trials of prostate cancer screening—one in the United States and one in Europe—have generated long-term data on how screening may affect prostate cancer mortality. And the two trials had different results.
In the European Randomized Study of Screening for Prostate Cancer (ERSPC), men who were screened for prostate cancer were less likely to die from prostate cancer than men who were not screened. That was not the case in the PLCO trial, which found that men who were screened did not have a lower risk of dying from prostate cancer than unscreened men. The trials were conducted very differently, and each had limitations, including a large number of unscheduled screenings (referred to as “contamination”) in the control group of the PLCO trial and a lack of standardized cancer treatment in ERSPC.
“So the question that we’re trying to answer is whether there is a range of screening benefits that is consistent with the results of both trials,” said Dr. Ruth Etzioni of the Fred Hutchinson Cancer Research Center, principal investigator of the CISNET prostate team. Researchers from both trials have allowed the CISNET team access to all of their data, down to the level of each individual patient, to resolve whether screening reduces prostate cancer deaths.
The CISNET team has spent years modeling the natural history of prostate cancer. “We can’t see when a person’s cancer begins…but we can see how disease is diagnosed in the population, at what ages people get diagnosed, and at what stages they get diagnosed. All of that informs us about what’s happening at a somewhat-below-the-surface level,” explained Dr. Etzioni.
The prostate modeling groups will use their knowledge of the natural history of prostate cancer and overall health and life histories of men in the United States “to ‘replicate’ what happened in ERSPC and PLCO on top of those life histories and disease histories,” Dr. Etzioni elaborated. “And when we replicate the two trials we’ll see if there is a range of true benefit, where we get something reasonably close to what was observed in both trials.”
The team is also beginning to look at how immediate versus delayed treatment may change the benefit/harm ratio of prostate cancer screening and at how the prevention of endpoints other than mortality—such as metastatic disease—may also alter that ratio. (See “Benefits and Harms of Prostate Cancer Screening.”)
Modeling Targeted Screening
For the first 10 years of the program, CISNET focused on four of the most common cancers in the United States: breast, prostate, lung, and colorectal. In 2010, it added a less common cancer—esophageal—which presents a different set of issues: determining how to screen for a cancer in a subpopulation of people with well-known risk factors for the disease.
“Esophageal cancer is not common enough to do population-based screening, but [doctors do] targeted screening based on individual risk,” explained Dr. Chin Hur of Massachusetts General Hospital, principal investigator of the esophageal cancer team.
“We chose a less common cancer [to include in CISNET] because the effort that we go through to find a relatively few esophageal cancers is incredibly inefficient,” commented Dr. Feuer. Although gastroesophageal reflux disease and a related condition called Barrett esophagus are known risk factors for esophageal cancer, relatively few people with either problem will develop the disease.
But doctors do not yet know how to identify which people with these conditions are most likely to develop esophageal cancer and may, therefore, benefit from targeted screening. “There’s huge potential to do things better,” said Dr. Feuer. The goal for the CISNET team is “to come up with cost-effective strategies to diminish the morbidity and mortality from esophageal cancer,” added Dr. Hur.
The esophageal team is developing three models using existing clinical trial data and is collaborating with modelers working at the molecular level of cancer. This so-called “multiscale modeling” will let the team build a more accurate representation of the natural history of esophageal cancer into their models. Once the models have been finalized, the researchers will use them to virtually “re-run” and analyze trials not only of endoscopic monitoring and radiofrequency ablation in people with Barrett esophagus but also other emerging strategies for preventing the progression of esophageal cancer.
Although endoscopic screening and radiofrequency ablation of Barrett esophagus have been tested in many smaller clinical studies, these trials have nowhere near the numbers of patients—or, therefore, the statistical power or general applicability—that large screening trials for breast, prostate, lung, and colorectal cancer have.
This poses a paradox for the modelers and for the esophageal cancer research community in general: “Where there is less clinical trial data available, there’s more uncertainty about the projections. At the same time, there is less data around to inform both clinical decision making and policy, so our results are more important. So, although there’s more uncertainty about [modeling], there’s also more need for it,” summarized Dr. Hur.
“We need to be very open and transparent about the limitations, explore those fully, and be careful about the conclusions of our analyses,” he said. “But [modeling] is better than someone just taking a best guess. It’s a systematic approach, with intense peer review and multiple modeling groups, that tries to distill the evidence that is out there.”
Over the past several years, the conversation about cancer screening has started to change within the medical community. Be it breast, prostate, or ovarian cancer, the trend is to recommend less routine screening, not more. These recommendations are based on an emerging—if counterintuitive—understanding that more screening does not necessarily translate into fewer cancer deaths and that some screening may actually do more harm than good.
Much of the confusion surrounding the benefits of screening comes from interpreting the statistics that are often used to describe the results of screening studies. An improvement in survival—how long a person lives after a cancer diagnosis—among people who have undergone a cancer screening test is often taken to imply that the test saves lives.
But survival cannot be used accurately for this purpose because of several sources of bias.
Sources of Bias
A graphic illustrating lead-time bias. Click to enlarge the image and to read the full caption. (Image from O. Wegwarth et al., Ann Intern Med, March 6, 2012:156)
Lead-time bias occurs when screening finds a cancer earlier than that cancer would have been diagnosed because of symptoms, but the earlier diagnosis does nothing to change the course of the disease. (See the graphic on the right for further explanation.)
Lead-time bias is inherent in any analysis comparing survival after detection. It makes 5-year survival after screen detection—and, by extension, earlier cancer diagnosis—an inherently inaccurate measure of whether screening saves lives. Unfortunately, the perception of longer life after detection can be very powerful for doctors, noted Dr. Donald Berry, professor of biostatistics at the University of Texas MD Anderson Cancer Center.
“I had a brilliant oncologist say to me, ‘Don, you have to understand: 20 years ago, before mammography, I’d see a patient with breast cancer, and 5 years later she was dead. Now, I see breast cancer patients, and 15 years later they’re still coming back, they haven’t recurred; it’s obvious that screening has done wonders,'” he recounted. “And I had to say no—that biases could completely explain the difference between the two [groups of patients].”
Another confounding phenomenon in screening studies is length-biased sampling (or “length bias”). Length bias refers to the fact that screening is more likely to pick up slower-growing, less aggressive cancers, which can exist in the body longer than fast-growing cancers before symptoms develop.
A graphic illustrating overdiagnosis bias. Click to enlarge the image and to read the full caption. (Image from O. Wegwarth et al., Ann Intern Med, March 6, 2012:156)
Dr. Berry likens screening to reaching into a bag of potato chips—you’re more likely to pick a larger chip because it’s easier for your hand to find, he explained. Similarly, with a screening test “you’re going to pick up the slower-growing cancers disproportionately, because the preclinical period when they can be detected by screening—the so-called sojourn time—is longer.”
The extreme example of length bias is overdiagnosis, where a slow-growing cancer found by screening never would have caused harm or required treatment during a patient’s lifetime. Because of overdiagnosis, the number of cancers found at an earlier stage is also an inaccurate measure of whether a screening test can save lives. (See the graphic on the left for further explanation.)
Because of these biases, the only reliable way to know if a screening test saves lives is through a randomized trial that shows a reduction in cancer deaths in people assigned to screening compared with people assigned to a control (usual care) group. In the NCI-sponsored randomized National Lung Screening Trial (NLST), for example, screening with low-dose spiral CT scans reduced lung cancer deaths by 20 percent relative to chest x-rays in heavy smokers. (Previous studies had shown that screening with chest x-rays does not reduce lung cancer mortality.)
However, improvements in mortality caused by screening often look small—and they are small—because the chance of a person dying from a given cancer is, fortunately, also small. “If the chance of dying from a cancer is small to begin with, there isn’t that much risk to reduce. So the effect of even a good screening test has to be small in absolute terms,” said Dr. Lisa Schwartz, professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice and co-director of the Veterans Affairs Outcomes Group in White River Junction, VT.
For example, in the case of NLST, a 20 percent decrease in the relative risk of dying of lung cancer translated to an approximately 0.4 percentage point reduction in lung cancer mortality (from 1.7 percent in the chest x-ray group to 1.3 percent in the CT scan group) after about 6.5 years of follow-up, explained Dr. Barry Kramer, director of NCI’s Division of Cancer Prevention.
A recent study published March 6 in the Annals of Internal Medicine by Dr. Schwartz and her colleagues showed how these relatively small—but real—reductions in mortality from screening can confuse even experienced doctors when pitted against large—but potentially misleading—improvements in survival.
Tricky Even for Experienced Doctors
To test community physicians’ understanding of screening statistics, Dr. Schwartz, Dr. Steven Woloshin (also of Dartmouth and co-director of the Veterans Affairs Outcomes Group), and their collaborators from the Max Planck Institute for Human Development in Germany developed an online questionnaire based on two hypothetical screening tests. They then administered the questionnaire to 412 doctors specializing in family medicine, internal medicine, or general medicine who had been recruited from the Harris Interactive Physician Panel.
The effects of the two hypothetical tests were described to the participants in two different ways: in terms of 5-year survival and in terms of mortality reduction. The participants also received additional information about the tests, such as the number of cancers detected and the proportion of cancer cases detected at an early stage.
The results of the survey showed widespread misunderstanding. Almost as many doctors (76 percent of those surveyed) believed—incorrectly—that an improvement in 5-year survival shows that a test saves lives as believed—correctly—that mortality data provides that evidence (81 percent of those surveyed).
About half of the doctors erroneously thought that simply finding more cases of cancer in a group of people who underwent screening compared with an unscreened group showed that the test saved lives. (In fact, a screening test can only save lives if it advances the time of diagnosis and earlier treatment is more effective than later treatment.) And 68 percent of doctors surveyed said they were even more likely to recommend the test if evidence showed that it detected more cancers at an early stage.
Doctors were three times more likely to say they would recommend the test supported by irrelevant survival data than the test supported by relevant mortality data.
In short, “the majority of primary care physicians did not know which screening statistics provide reliable evidence on whether screening works,” Dr. Schwartz and her colleagues wrote. “They were more likely to recommend a screening test supported by irrelevant evidence…than one supported by the relevant evidence: reduction in cancer mortality with screening.”
Teaching the Testers
“In some ways these results weren’t surprising, because I don’t think [these statistics] are part of the standard medical school curriculum,” said Dr. Schwartz.
“When we were in medical school and in residency, this wasn’t part of the training,” Dr. Woloshin agreed.
“We should be teaching residents and medical students how to correctly interpret these statistics and how to see through exaggeration,” added Dr. Schwartz.
Some schools have begun to do this. The University of North Carolina (UNC) School of Medicine has introduced a course called the Science of Testing, explained Dr. Russell Harris, professor of medicine at UNC. The course includes modules on 5-year survival and mortality outcomes.
Drs. Schwartz and Woloshin also think that better training for reporters, advocates, and anyone who disseminates the results of screening studies is essential. “A lot of people see those [news] stories and messages, so people writing them need to understand,” said Dr. Woloshin.
Patients also need to know the right questions to ask their doctors. “Always ask for the right numbers,” he recommended. “You see these ads with numbers like ‘5-year survival changes from 10 percent to 90 percent if you’re screened.’ But what you always want to ask is: ‘What’s my chance of dying [from the disease] if I’m screened or if I’m not screened?'”
In the United States, we are bombarded with information on cancer screening. Radio advertisements try to lure people to clinics by touting the benefits of lung cancer screening. Some cancer advocacy groups encourage prostate or breast cancer screening. And the media emphasizes the benefits of screening. But many people do not understand the complexity of cancer screening. Nor do they know that most expert organizations recommend that patients be aware of the potential risks and benefits of a screening test.
Screening is looking for cancer in an asymptomatic individual only because he or she is the age or gender of people at risk for the disease.
While the wise use of screening tests can save lives, and screening is one important element in the 20 percent decline in the cancer death rate over the last 20 years, screening is complicated.
As a screening expert, I worry that many people view these issues too simplistically. Cancer screening should be practiced with some caution. In assessing the science behind common screening tests, most expert panels have advised that the patient be told about the potential risks and benefits associated with a screening test, as well as the diagnostic tests and treatments associated with a positive result.
Patients should understand that no screening test is 100 percent accurate. Any test will miss some cancers. For example, high-quality mammography misses at least 20 percent of tumors, and prostate cancer screening misses at least half of all prostate cancers. Screening can also cause anxiety. And, in rare cases, screening can lead to treatment and diagnostic interventions that can even cause an early death.
In some cases, screening can find an early cancer, yet still lead to unnecessary treatment and all of the side effects associated with the treatment. These cancers are overdiagnosed. They fulfill all the criteria for cancer and look like cancer under a microscope, but if left alone they will not progress and kill. Some studies suggest that about one-third of screen-detected localizedbreast cancers and up to 70 percent of localized prostate cancers are overdiagnosed. A number of other cancers, especially cancers of the thyroid and lung, are also overdiagnosed.
Because of overdiagnosis, greater survival time after diagnosis or larger proportions of patients alive 5 years after diagnosis are not necessarily evidence of benefit from screening. This is because some patients might have been overdiagnosed, and some patients may have been diagnosed earlier but not lived longer. (See “Crunching the Numbers:What Cancer Screening Statistics Really Tell Us.”)
Nevertheless, screening is an important part of the effort to reduce the number of lives lost to cancer. And, as this special issue of the NCI Cancer Bulletin highlights, a tremendous amount of research focused on improving the effectiveness and efficiency of cancer screening is under way.
Many investigators, for example, are developing the next generation of screening tests for a host of cancers. This is painstaking research that requires patience and perseverance, but the progress to date is encouraging.
Other researchers are trying to solve one of the most persistent and pernicious problems in cancer care—and our health care system as a whole: disparities. Any gynecologic oncologist will tell you that Pap and HPV testing can prevent cervical cancer. But they will also tell you that they are treating too many women—in many cases, African American women or those without health insurance—with late-stage cervical cancer who were inadequately screened or never screened at all. An innovative program, called PROSPR, is aimed at reversing that trend by improving the entire cancer screening process, with a particular focus on underserved populations.
Another effort, called CISNET, is using sophisticated computer modeling to find how best to extrapolate the results of cancer screening studies, including large randomized trials, to the general population. This work includes a deeper analysis of the results of the National Lung Screening Trial, a study that focused on people at high risk for lung cancer based on their smoking history.
This special issue of the NCI Cancer Bulletin also includes several discussions with noted screening experts about interpreting cancer screening statistics and how we think and talk about screening, especially during conversations between patients and physicians.
The breadth of the research being done to improve how we screen for cancer is extremely encouraging. Although progress may not always come as quickly as we might like, given the expertise and dedication of investigators working in this area, the future holds great promise.
Dr. Otis W. Brawley Chief Medical and Scientific Officer, American Cancer Society Professor of Hematology, Medical Oncology, Medicine, and Epidemiology, Emory University
The 2004 statement recommended against routine screening in adults not at increased risk and found no evidence for or against screening those at high risk.
The USPSTF’s evidence review on adult screening points out that the CDC‘s recent recommendation to screen all baby-boomers was based on cost-effectiveness analyses and that information on the clinical outcomes of such strategies is needed. Targeting screening of high-risk patients will miss some patients with infection, they observe.
The review on preventing mother-child transmission finds that no intervention has been shown to reduce risk — including the avoidance of breast-feeding.
ARYAN'S BLOG 
