Association of Screening Lower Endoscopy With Colorectal Cancer Incidence and Mortality in Adults Older Than 75 Years

Abstract

Importance: Evidence indicates that screening for colorectal cancer (CRC) beginning at 50 years of age can detect early-stage CRC and premalignant neoplasms (eg, adenomas) and thus prevent CRC-related mortality. At present, the US Preventive Services Task Force recommends continuing CRC screening until 75 years of age and individualized decision-making for adults older than 75 years, while accounting for a patient's overall health and screening history. However, scant data exist to support these recommendations.

Objective: To examine the association of lower gastrointestinal tract screening endoscopy with the risk of CRC incidence and CRC-related mortality in older US adults.

Design, setting, and participants: This prospective cohort study of health care professionals in the US included data from the Nurses' Health Study (NHS) and Health Professionals Follow-up Study (HPFS) from January 1, 1988, through January 31, 2016, for the HPFS and June 30, 2016, for the NHS. Data were analyzed from May 8, 2019, to July 9, 2020.

Exposures: History of screening sigmoidoscopy or colonoscopy (routine/average risk or positive family history) to 75 years of age and after 75 years of age, assessed every 2 years.

Main outcomes and measures: Incidence of CRC and CRC-related mortality confirmed by National Death Index, medical records, and pathology reports.

Results: Among 56 374 participants who reached 75 years of age during follow-up (36.8% men and 63.2% women), 661 incident CRC cases and 323 CRC-related deaths were documented. Screening endoscopy after 75 years of age was associated with reduced risk of CRC incidence (multivariable hazard ratio [HR], 0.61; 95% CI, 0.51-0.74) and CRC-related mortality (HR, 0.60; 95% CI, 0.46-0.78), regardless of screening history. The HR comparing screening with nonscreening after 75 years of age was 0.67 (95% CI, 0.50-0.89) for CRC incidence and 0.58 (95% CI, 0.38-0.87) for CRC-related mortality among participants who underwent screening endoscopy before 75 years of age, and 0.51 (95% CI, 0.37-0.70) for CRC incidence and 0.63 (95% CI, 0.43-0.93) for CRC-related mortality among participants without a screening history. However, screening endoscopy after 75 years of age was not associated with risk reduction in CRC death among participants with cardiovascular disease (HR, 1.18; 95% CI, 0.59-2.35) or significant comorbidities (HR, 1.17; 95% CI, 0.57-2.43).

Conclusions and relevance: In this cohort study, endoscopy among individuals older than 75 years was associated with lower risk of CRC incidence and CRC-related mortality. These data support continuation of screening after 75 years of age among individuals without significant comorbidities.

Figure.. Screening Lower Endoscopy After 75 Years of Age and Risk of Colorectal Cancer (CRC) Incidence and Mortality in Subgroups of Family History of CRC, Cardiovascular Disease, and Cardiovascular Risk Factors

Hazard ratios (HRs) were calculated from Cox proportional hazards regression models that were stratified by age, questionnaire cycle, and cohort and further adjusted for family history of CRC, body mass index, physical activity, smoking, alcohol consumption, aspirin use, use of other nonsteroidal anti-inflammatory drugs, multivitamin use, prior screening endoscopy, and intake of total calories, calcium, folate, or red and processed meat. We additionally adjusted for menopausal hormone use in women. ^aIncludes cardiovascular disease (myocardial infarction or stroke), hypertension, hypercholesterolemia, and diabetes. Covariates at 75 years of age were used in these analyses.