Colorectal Cancer and Mortality Risk Among Older Adults With vs Without Adenoma on Prior Colonoscopy

Area of Science:

• Gastroenterology
• Oncology
• Geriatrics

Background:

• Colorectal cancer (CRC) risk in older adults with a history of adenoma is not well-established.
• Current guidelines suggest against repeat colonoscopies for older adults without adenoma history.

Purpose of the Study:

• To estimate cumulative CRC risks, non-CRC mortality, and all-cause mortality in adults aged 75+ with vs. without prior adenoma.
• To inform decisions regarding surveillance colonoscopy in older populations.

Main Methods:

• Retrospective cohort study of 91,952 adults who underwent colonoscopy before age 75 within the US Department of Veterans Affairs.
• Comparison of cumulative CRC incidence, CRC death, non-CRC death, and all-cause mortality at 10-year follow-up.
• Stratification of outcomes by frailty index for individuals with prior adenoma.

Main Results:

• At 10-year follow-up, CRC incidence was 1.1% in those with prior adenoma vs. 0.7% without (P < .001).
• CRC death incidence was 0.5% with adenoma vs. 0.4% without (P = .005).
• Non-CRC death cumulative incidence ranged from 46.9% to 48.4%, significantly exceeding CRC risks across all frailty levels.

Conclusions:

• Adults 75+ with prior adenoma have a higher likelihood of CRC and CRC death compared to those without adenoma.
• However, the cumulative risks for CRC and CRC death are low and substantially overshadowed by competing non-CRC mortality risks.
• Older adults may consider deprioritizing surveillance colonoscopy in favor of other health concerns.