Should colorectal cancer screening be considered in elderly persons without previous screening? A cost-effectiveness analysis

Abstract

Background: The U.S. Preventive Services Task Force recommends against routine screening for colorectal cancer (CRC) in adequately screened persons older than 75 years but does not address the appropriateness of screening in elderly persons without previous screening.

Objective: To determine at what ages CRC screening should be considered in unscreened elderly persons and to determine which test is indicated at each age.

Design: Microsimulation modeling study.

Data sources: Observational and experimental studies.

Target population: Unscreened persons aged 76 to 90 years with no, moderate, and severe comorbid conditions.

Time horizon: Lifetime.

Perspective: Societal.

Intervention: One-time colonoscopy, sigmoidoscopy, or fecal immunochemical test (FIT) screening.

Outcome measures: Quality-adjusted life-years gained, costs, and costs per quality-adjusted life-year gained.

Results of base-case analysis: In unscreened elderly persons with no comorbid conditions, CRC screening was cost-effective up to age 86 years. Screening with colonoscopy was indicated up to age 83 years, sigmoidoscopy was indicated at age 84 years, and FIT was indicated at ages 85 and 86 years. In unscreened persons with moderate comorbid conditions, screening was cost-effective up to age 83 years (colonoscopy indicated up to age 80 years, sigmoidoscopy at age 81 years, and FIT at ages 82 and 83 years). In unscreened persons with severe comorbid conditions, screening was cost-effective up to age 80 years (colonoscopy indicated up to age 77 years, sigmoidoscopy at age 78 years, and FIT at ages 79 and 80 years).

Results of sensitivity analyses: Results were most sensitive to assuming a lower willingness to pay per quality-adjusted life-year gained.

Limitation: Only persons at average risk for CRC were considered.

Conclusion: In unscreened elderly persons CRC screening should be considered well beyond age 75 years. A colonoscopy is indicated at most ages.

Primary funding source: National Cancer Institute.

Figure 1. The Cost-Effectiveness of Once-Only Colonoscopy, Sigmoidoscopy, and FIT Screening Compared with No Screening in Elderly Without Prior Screening with No (A), Moderate (B), and Severe Comorbidity (C) (3% discounted)*†

*Individuals are classified as having moderate comorbidity if diagnosed with an ulcer, rheumatologic disease, peripheral vascular disease, diabetes, paralysis, or cerebrovascular disease and in case of a history of acute myocardial infarction; as having severe comorbidity if diagnosed with chronic obstructive pulmonary disease, congestive heart failure, moderate or severe liver disease, chronic renal failure, dementia, cirrhosis and chronic hepatitis, or AIDS; and as having no comorbidity if none of these conditions is present. †The dashed red line indicates a threshold for the willingness to pay per QALY gained of $100,000. Screening strategies costing less than $100,000 per QALY gained are considered cost-effective. ‡Screening strategy associated with a net health loss, rather than a benefit (Table 2 and Appendix Table 3).

Figure 2. The Incremental Costs-Effectiveness of the Efficient Screening Strategies in Elderly Without Prior Screening with No (A), Moderate (B), and Severe Comorbidity (C) (results per 1,000 individuals; 3% discounted)*†‡

*Individuals are classified as having moderate comorbidity if diagnosed with an ulcer, rheumatologic disease, peripheral vascular disease, diabetes, paralysis, or cerebrovascular disease and in case of a history of acute myocardial infarction; as having severe comorbidity if diagnosed with chronic obstructive pulmonary disease, congestive heart failure, moderate or severe liver disease, chronic renal failure, dementia, cirrhosis and chronic hepatitis, or AIDS; and as having no comorbidity if none of these conditions is present. †In elderly without prior screening with no, moderate, and severe comorbidity, none of the screening strategies are cost-effective from age 87, 84, and 81 onwards, respectively (Figure 1). ‡For each age, the efficient screening strategies are connected by an efficiency fron er. A solid line indicates that the incremental cost-effectiveness ratio of a screening strategy is lower than $100,000 per QALY gained, implying that the strategy is considered cost-effective. A dashed line indicates that the incremental cost-effectiveness ratio of a screening strategy exceeds $100,000 per QALY gained, implying that the strategy is not considered cost-effective.