Adenomas Linked to Greater Risk of Colorectal Cancer, All-Cause Mortality

Aasma Shaukat, MD, MPH

Credit: NYU Langone Health

New research is shedding light on a heightened risk of colorectal cancer (CRC) in patients with both nonadvanced and advanced adenomas detected during colonoscopy, highlighting the importance of surveillance colonoscopy in this population and the need for more frequent screening among those with advanced adenomas.¹

Leveraging data from the Minnesota Colon Cancer Control Study, the present analysis found individuals with adenomas at colonoscopy, regardless of whether or not they were advanced, were at a greater risk of developing CRC than those with no adenomas. Additionally, findings showed participants with advanced adenomas were at increased risk of both CRC mortality and all-cause mortality.¹

“Studies have reported the association of advanced adenomas with increased risk of CRC and CRC-related death over the following 5 to 15 years compared with having no advanced adenomas. The association of nonadvanced adenomas with CRC incidence and mortality after colonoscopy is less clear,” Aasma Shaukat, MD, MPH, a gastroenterologist and Robert M. and Mary H. Glickman Professor of Medicine at New York University Grossman School of Medicine, and colleagues wrote.¹ “However, to our knowledge, no studies have evaluated the association of adenomas and advanced adenomas with all-cause mortality.”

According to the American Cancer Society, from 2012 to 2021, incidence rates for CRC dropped by about 1% each year. However, this downward trend is largely limited to older adults – in people younger than 50 years of age, rates have increased by 2.4% per year from 2012 to 2021. Accordingly, the US Preventive Services Task Force changed the recommended age to begin CRC screening with colonoscopy from 50 to 45 years of age.^2,3

Despite the advent of several noninvasive tests for CRC screening, colonoscopy continues to be viewed as the “gold standard” because it is highly sensitive and allows for the detection and removal of precancerous polyps that could eventually become CRC.

To investigate the association between nonadvanced and advanced adenomas with CRC incidence and mortality and all-cause mortality, investigators collected data from a multicenter, prospective cohort study of participants in the Minnesota fecal occult blood randomized clinical trial, which included 46,551 males and females ≥ 45 years of age, 10,584 of whom underwent colonoscopy after a positive fecal occult blood test. Data were collected between 1975 and 2013.¹

Colonoscopy findings were categorized as advanced adenoma, defined as 1 cm, high-grade dysplasia or tubule-villous or villous histology; nonadvanced adenoma, defined as <1 cm without advanced histology; or no adenoma.¹

Investigators estimated the cumulative incidence of CRC with a competing risk of mortality; CRC mortality with a competing risk of other-cause mortality; and overall mortality. Analysis was conducted between November 2023 and November 2024.¹

Among the 10,584 participants who underwent colonoscopy, the majority were male (50.1%) with a mean age of 69 (Standard deviation [SD], 8) years. The 20-year cumulative incidence of CRC was 1.8% (95% CI, 1.5%-2.1%) for those with normal examinations; 3.9% (95% CI, 2.7%-5.4%) for those with nonadvanced adenomas, and 5.5% (95% CI, 4.1%-7.2%) for those with advanced adenomas.¹

Investigators noted participants with nonadvanced (subdistribution hazard ratio [SHR], 2.24; 95% CI, 1.54-3.24; P <.001) and advanced (SHR, 3.24; 95% CI, 2.32-4.52; P <.001) adenomas were significantly more likely to develop CRC than those with no adenomas.¹

Further analysis revealed participants with advanced adenomas were at a significantly increased risk of CRC mortality (SHR, 2.20; 95% CI, 1.36-3.57; P <.001) and all-cause mortality (HR, 1.12; 95% CI, 1.03-1.21; P = .005) compared with participants with no adenomas. However, investigators pointed out participants with nonadvanced adenomas did not have a statistically significant increase in CRC mortality or all-cause mortality relative to those with no adenomas.¹

“Our study underscores the importance of surveillance colonoscopy for individuals with advanced and nonadvanced adenomas and supports current recommendations of more frequent surveillance for those with advanced adenomas,” investigators concluded.¹

References

1. Shaukat A, Goffredo P, Wolf JM, et al. Advanced Adenoma and Long-Term Risk of Colorectal Cancer, Cancer-Related Mortality, and Mortality. JAMA Network Open. doi:10.1001/jamanetworkopen.2024.59703

2. American Cancer Society. Key Statistics for Colorectal Cancer. January 16, 2025. Accessed February 13, 2025. https://www.cancer.org/cancer/types/colon-rectal-cancer/about/key-statistics.html

3. USPSTF. Colorectal Cancer: Screening. May 18, 2021. Accessed February 13, 2025. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening