INDIANAPOLIS, IN — Until recent decades, colorectal cancer was viewed as primarily a disease of the elderly, with average occurrence in their late 60s for men and early 70s for women.
What is puzzling researchers and clinicians now, however, is the troubling increase in the incidence of CRC in adults younger than age 50 in the United States and other high-income countries. Studies have shown that early-onset CRC (EOCRC) now makes up about 10% of new cases of the cancer. An increase in mortality of younger patients has accompanied the rising trend.
Researchers from the Richard L. Roudebush VAMC, Indiana University School of Medicine, and the Regenstrief Institute, all in Indianapolis, pointed out in a recent that screening 45- to 49-year-olds for colorectal cancer is “relatively new with uncertain uptake thus far. Furthermore, half of EOCRC occurs in persons < 45 years old. Using risk factors may help 45- to 49-year-olds accept screening and may identify younger persons for whom earlier screening should be considered.”
In an article in Cancer Prevention Research, the study team described the results of their efforts to identify EOCRC risk factors that could be used for decisions about early screening. Using electronic databases and medical record review, researchers compared male veterans ages 35 to 49 years diagnosed with sporadic EOCRC (2008-2015) matched 1:4 to clinic and colonoscopy controls without colorectal cancer. Excluded were those with established inflammatory bowel disease, high-risk polyposis, and nonpolyposis syndromes, prior bowel resection, and high-risk family history.
The study also collected information about sociodemographic and lifestyle factors, family and personal medical history, physical measures, vital signs, medications, and laboratory values 6 to 18 months prior to case diagnosis.
Ultimately, the researchers analyzed 600 cases of sporadic EOCRC among veterans with a mean age of 45.2 and 66% white – which was similar to primary care clinic and colonoscopy controls.
The study determined that [independent risk factors included age, cohabitation and employment status, body mass index (BMI), comorbidity, colorectal cancer, or other visceral cancer in a first- or second-degree relative (FDR or SDR), alcohol use, exercise, hyperlipidemia, use of statins, NSAIDs, and multivitamins.
“Validation c-statistics were 0.75-0.76 for the full model and 0.74-0.75 for the parsimonious model, respectively,” the authors wrote. “These independent risk factors for EOCRC may identify veterans for whom colorectal cancer screening prior to age 45 or 50 years should be considered.”
The American Cancer Society has reported that, among older adults, cancer death rates continued to decline 0.6% in those 50 to 64 and 2.6% in those 65 and older from 2013-2017, although not as rapidly as from 2004-2013, when the rates were 1% and 3.3%, respectively.
On the other hand, CRC death rates have increased in individuals younger than 50 years of age by 1.3% per year, since 2004.
In an accompanying commentary, Erin M. Siegel, PhD, MPH, of the H. Lee Moffitt Cancer Center & Research Institute in Tampa, and colleagues wrote, “Early-onset colorectal cancer (EOCRC) is increasing at alarming rates and identifying risk factors is a high priority. There is a need to develop risk stratification approaches for colorectal cancer screening among younger populations.”
The commentary added, “Although there is a growing body of evidence identifying risk factors for EOCRC, including the report by Imperiale and colleagues in this issue, risk stratification for EOCRC screening has not been implemented into practice. This publication highlights how essential it is to bring research findings into practice and bridge the gaps between developing risk prediction modeling in epidemiology and implementation science. While encouraging, we are still a long way off from having a clinically applicable risk prediction tool.”
- Imperiale TF, Myers LJ, Barker BC, Larson J, Stump TE, Daggy JK. Risk Factors for Early-onset Sporadic Colorectal Cancer in Male Veterans. Cancer Prev Res (Phila). 2023 Sep 1;16(9):513-522. doi: 10.1158/1940-6207.CAPR-22-0506. PMID: 37079701.
- Siegel EM, Ulrich CM, Shibata D. Risk Stratification for Early-onset Colorectal Cancer Screening: Are We Ready for Implementation? Cancer Prev Res (Phila). 2023 Sep 1;16(9):479-481. doi: 10.1158/1940-6207.CAPR-23-0239. PMID: 37655450.
