In patients aged greater than 75 years, endoscopy was associated with lower risk for colorectal cancer incidence and related mortality, according to study results published in JAMA Oncology.

Researchers used data from the Nurses’ Health Study and Health Professionals Follow-up Study for this prospective cohort study. A total of 56,374 participants who reached the age of 75 during follow-up without being diagnosed with colorectal cancer were included. Among this cohort, 36.8% of patients were men and 63.2% were women.

A total of 661 incident colorectal cancer cases and 323 cancer-related deaths were documented, consisting of 385,309 and 458,675 person-years of follow-up, respectively. When comparing patients who underwent screening vs those who didn’t, the incidence rate difference for colorectal cancer occurrence was 74.1 per 100,000 person-years and  7.9 per 100,000 person-years for cancer morality. After adjusting for screening history, screening endoscopy in patients aged greater than 75 years remained significantly associated with reduced risk for colorectal cancer incidence (hazard ratio [HR], 0.61; 95% CI, 0.51-0.74) and related mortality (HR, 0.60; 95% CI, 0.46-0.78).

Among patients who underwent screening before reaching 75 years of age, continuing screening after age 75 was associated with a reduced risk for incident colorectal cancer (HR, 0.67; 95% CI, 0.50-0.89) and related mortality (HR, 0.58; 95% CI, 0.38-0.87) compared with those who stopped screening. Similarly, when comparing screening vs non-screening among patients who never underwent screening at age 75 or younger, the HR for incidence of colorectal cancer was 0.51 (95% CI, 0.37-0.70) and 0.63 (95% CI, 0.43-0.93) for related mortality. However, the risk for cancer-related mortality in patients who continued screening beyond age 75 was not reduced in those with a history of cardiovascular disease or 3 or more comorbidities.

Study limitations included researchers not knowing the exact dates screening took place, thus inhibiting accurate identification of screening-detected colorectal cancer cases. Additionally, due to a relatively small number of incident cases in the subgroups, researchers did not assess how patient comorbidities may affect associations between screening after age 75 and cancer incidence and mortality. Finally, the study cohort was relatively homogenous, highlighting the need for future studies that include different ethnic groups.

According to researchers, “These findings provide empirical evidence supporting the continuation of screening endoscopy among many adults older than 75 years for prevention of [colorectal cancer] incidence and death, especially those who do not have significant comorbidities.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Ma W, Wang K, Nguyen LH, et al. Association of screening lower endoscopy with colorectal cancer incidence and mortality in adults older than 75 years. JAMA Oncol. Published online May 20, 2021. doi:10.1001/jamaoncol.2021.1364