Colorectal Cancer Incidence Has Increased Among Younger Men, Not Women, According to Recent Study

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The incidence of colorectal cancer (CRC) increased between 1988 and 2018 among men but not women aged less than 50 years who were asymptomatic, suggesting that sex should be considered when determining screening age, according to results of a recent Austrian study.

“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,” wrote researchers in JAMA Network Open.

Current guidance from the American College of Physicians recommends clinicians start screening for CRC in asymptomatic adults at age 50 years.

According to first author Daniela Penz, MD, of the Austrian Society of Gastroenterology and Hepatology, and colleagues, CRC incidence and mortality has decreased in the US and several countries in Europe over the past 3 decades among adults aged ≥55 years, “which could be an effect of higher adherence to CRC screening programs.”

“At the same time, an increase in mortality and incidence rates among younger patients was noticed,” continued Penz and coauthors. “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.”

Researchers conducted the current study to analyze the prevalence and number needed to screen (NNS) for adenomas, advanced adenomas (AAs), and serrated lesions, as well as CRC incidence in persons aged ≥20 years. They evaluated 296 170 patients (median age, 60 years; 50.9% women) who received a screening colonoscopy within a national screening colonoscopy registry from 2008 to 2018 in Austria. In addition, the incidence of CRC was analyzed using data from Statistic Austria from 1988 to 2018.

Among the cohort, 11 103 (3.7%) were aged <50 years, according to the study.

FINDINGS

Investigators found that 10.5% (NNS=9) of participants aged <50 years and 21.9% (NNS=5) aged ≥50 years had adenomas, while 3.9% (NNS=26) and 6.9% (NNS=15), respectively, had at least 1 AA. Among patients aged 40 to 44 years, there was at least 1 adenoma present in 14.2% (NNS=7) of men and 8.1% (NNS=12) of women.

Penz and colleagues reported that 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 of the same age groups.

From 2008 to 2018, the prevalence of adenomas increased from 12.4% to 14.1% among persons aged <50 years and from 21.8% to 28.2% among those aged ≥50 years. Change in the prevalence of AA during the same time was 4% to 5.2% and 7.3% to 6.8%, respectively, noted investigators.

In regard to CRC, investigators found CRC incidence per 100 000 individuals changed from 9.1 incidents in 1988 to 10.2 in 2018 among men aged <50 years (average annual percent change [AAPC] 0.5%, 95% CI 0.1%-1.0%) and from 9.7 to 7.7 incidents among women of the same age (AAPC –0.2%, 95% CI –0.7% to 0.3%). Among participants aged ≥50 years, CRC incidence shifted from 217 in 1988 to 143 in 2018 (AAPC –1.2%, 95% CI, –1.3% to –1.1%) and from 168 in 1988 to 97 in 2018 (AAPC –1.8%, 95% CI –1.9% to –1.6%) among men and women, respectively.

Study limitations include a lack of data regarding lifestyle factors (eg, smoking, diabetes, body mass index) or comorbidities and the fact that it did not analyze factors associated with CRC.

“Therefore, further studies are necessary to evaluate the reasons for increasing incidences of CRC in younger adults, particularly males,” wrote Penz et al.

Source: Penz D, Waldmann E, Hackl M, et al. Colorectal cancer and precursor lesion prevalence in adults younger than 50 years without symptoms. JAMA Netw Open. 2023;6:e2334757.