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Key takeaways:

• From 2008 to 2018, prevalence of adenomas changed from 12.4% to 14.1% among those younger than 50 years.
• Colorectal cancer incidence per 100,000 changed from 9.1 in 1988 to 10.2 in 2018 among younger men.

Colorectal cancer incidence has increased since 1988 among men but not women younger than 50 years, suggesting that patient sex should be factored in when determining screening age, data from an Austrian study showed.

“CRC incidence and mortality decreased in the U.S. and many European countries over the last 30 years among adults aged 55 years and older, which could be an effect of higher adherence to CRC screening programs,” Daniela Penz, MD, of the Austrian Society of Gastroenterology and Hepatology, and colleagues wrote in JAMA Network Open. “At the same time, an increase in mortality and incidence rates among younger patients was noticed.”

They continued, “Despite the evidence of an increase in CRC incidence among younger adults, data about the prevalence of precursor lesions, such as adenomas, among younger individuals, especially those without symptoms, are still missing.”

Seeking to analyze the prevalence and number needed to screen (NNS) for adenomas, advanced adenomas and serrated lesions, as well as CRC incidence in individuals older than 20 years, researchers evaluated 296,170 patients (median age, 60 years; 50.9% women) who underwent screening colonoscopy within the Austrian quality assurance program between 2008 and 2018. They also analyzed CRC incidence using Statistic Austria data from 1988 to 2018. Of those included in the study, 11,103 (3.7%) were aged younger than 50 years.

Analysis showed 10.5% (NNS = 9) of individuals younger than 50 years and 21.9% (NNS = 5) aged 50 years and older had adenomas, while 3.9% (NNS = 26) and 6.9% (NNS = 15), respectively, had at least one advanced adenoma. Among patients aged 40 to 44 years, there was at least one adenoma present in 14.2% (NNS = 7) of men and 8.1% (NNS = 12) of women.

The prevalence of adenomas among men aged 45 to 49 years vs. 50 to 54 years was 17.1% (NNS = 6) vs. 20.2% (NNS= 5) compared with 10.2% (NNS = 10) vs. 12.4% (NNS = 8), respectively, among women.

From 2008 to 2018, prevalence of adenomas changed from 12.4% to 14.1% among those younger than 50 years and from 21.8% to 28.2% among those 50 years and older; change in advanced adenoma prevalence during the same time period was 4% to 5.2% and 7.3% to 6.8%, respectively.

For CRC, incidence per 100,000 individuals changed from 9.1 in 1988 to 10.2 in 2018 among men younger than 50 years (average annual percent change [AAPC] = 0.5%; 95% CI, 0.1-1) and from 9.7 to 7.7 among women of the same age (AAPC = –0.2%; 95% CI, –0.7 to 0.3). CRC incidence shifted from 217 to 143 (AAPC = –1.2%; 95% CI, –1.3 to –1.1) and 168 to 97 (AAPC = –1.8%; 95% CI, –1.9 to –1.6) among men and women, respectively, aged 50 years or older.

“This cohort study found that the prevalence of adenomas and advanced adenomas increased among younger adults in Austria,” Penz and colleagues concluded. “CRC incidence has increased since 1988 in males but not females younger than age 50 years.”

They continued: “These findings suggest that patient sex should be considered as a factor when determining the age for starting screening in further recommendations. Based on this study, screening should have started at age 40 years for males and age 50 years or even later, around age 55 years, for females.”