Association between colonoscopy and colorectal cancer risk in adults aged 75 to 85 years: a nationwide...

Although colorectal cancer (CRC) incidence increases with age, the benefit of colonoscopy in adults aged ≥75 years is debated because of shorter life expectancy and procedural risks. Given limited real-world data, we evaluated the association between colonoscopy and incident CRC in adults aged 75 to 85 years.

Using the Korean National Health Insurance Service database (2004-2020), we conducted a nationwide study of adults aged 75 to 85 years. Participants were 1:1 propensity score-matched into colonoscopy cohort (CsC) and noncolonoscopy cohort (NCsC). Adjusted hazard ratios (aHRs) for incident CRC were estimated using Cox proportional hazards models, stratified by age and sex.

After matching, 19,005 individuals were included in each cohort. CRC occurred in 2.8% and 3.7% of participants in the CsC and NCsC, respectively. Colonoscopy was associated with a significantly reduced CRC risk among adults aged 75 to 79 years (aHR, 0.75; 95% CI, 0.66-0.84), whereas no significant protective effect was observed among those aged 80 to 85 years (aHR, 0.77; 95% CI, 0.57-1.03). The attenuation of benefit in the early 80s was most pronounced in women (aHR, 1.32; 95% CI, 0.81-2.15). Alcohol consumption was the only modifiable factor consistently associated with an increased CRC risk.

Colonoscopy was associated with reduced CRC incidence in adults aged 75 to 79 years but not in those aged 80 to 85 years, particularly women. These findings highlight the need for individualized screening considering life expectancy and competing risks in older adults.