“Should you still get a colonoscopy?” “A landmark study…found only meager benefits for the group of people invited to get the procedure.” “Doctors push back against European study that casts doubt.”

These are just some of the media reports surrounding the Nordic-European Initiative on Colorectal Cancer (NordICC) Study Group paper, “Effect of colonoscopy screening on risks of colorectal cancer and related death,” published in The New England Journal of Medicine in October.

Having witnessed the recent explosion of medical misinformation, especially during the COVID-19 pandemic, I initially wondered why this study would be circulated by one of the most respected medical journals in the world. After reading the study design in more detail, I realized that the critical shortcoming of the study is the terminology employed by the authors; specifically, the interpretation of the word “screening.”

Screening saves lives

As a gastroenterologist with a primary focus in colorectal cancer screening and prevention, I recognize that colorectal cancer is the second leading cause of cancer death among American men and women combined. Colorectal cancer affects more than 150,000 Americans every year, with 52,580 expected deaths in 2022 alone. It is estimated that 60% of these deaths could be prevented with screening.

The good news is that colorectal cancer screening rates in the U.S. have steadily increased since the 1980s, with a subsequent decrease in colorectal cancer incidence. As of 2020, 71.6% of adults aged 50 to 75 years reported being up to date with colorectal cancer screening using various modalities. However, the lifetime risk for developing colorectal cancer for an average-risk American is still one in 24. In comparison, the lifetime risk of dying in a car crash is estimated to be one in 107.

Invitation does not equal screening

The NordICC trial is a randomized controlled trial involving healthy men and women aged 55 to 64 years from population registries in Poland, Norway, Sweden and the Netherlands between 2009 and 2014. Researchers randomly assigned individuals in a 1:2 ratio to receive an invitation to undergo a colonoscopy or to receive no invitation. The invitation consisted of a letter with the appointment date and time for a prescheduled colonoscopy, educational pamphlets, and contact information. This letter was mailed about 6 weeks before the scheduled date. No other colorectal cancer screening tests were offered.

Colonoscopy was performed in 42% of the invited group, with a 50% decrease in colorectal cancer-associated death. The study estimated a 31% decrease in colorectal cancer incidence if all study participants had undergone colonoscopy. However, the risk for death from any cause in the invited group (11.03%) and the usual care group (11.04%) showed no significant difference.

The results of this study clearly show that screening colonoscopy reduces colorectal cancer — when it is performed. This translates to decreased cancer treatment and surveillance costs, as well as a diminished emotional burden. In the U.S., the conversation about completing a colorectal cancer screening test may occur over the course of several clinic visits, as patients are often hesitant to discuss “a scope going up there.” If a patient refuses screening, this decision is documented in their medical record and can be reassessed at a future appointment. Mailing a letter with an assigned procedure date and time overlooks an opportunity for patients to participate in the decision-making process. As evidenced by the study’s colonoscopy completion rate, most invitation letters likely ended up in the trash; 58% of the invited study group did not undergo screening.

In actuality, the NordICC trial assessed the response to mailed invitation, rather than the effectiveness of screening colonoscopy. Regrettably, the title wording invites misinterpretation because “screening” is used to indicate the invited study group as a whole, rather than the individuals who actually completed colonoscopy. In addition, 29% of endoscopists had an adenoma detection rate — a surrogate marker for colonoscopy quality — less than the minimum recommended threshold of 25%; as such, the decrease in colorectal cancer-associated death may have been even more pronounced with high-quality colonoscopies. Of note, the Netherlands, one of the countries involved in the NordICC trial, implemented a national screening program in 2014 with clear reduction in colorectal cancer.

Read more than the headline

Unfortunately, we live in a time when many people read headlines rather than the details. Frequently, news media is sensationalized before the facts are fully understood. Having seen the physical and emotional damage that colorectal cancer can cause, I strongly believe in colorectal cancer screening — using both invasive and noninvasive screening tests — as a preventive measure. The controversy surrounding the findings of the NordICC trial highlights the need for careful evaluation before making judgements. In an age where medical misinformation is widespread, this caveat is important for all of us to remember.