Cost Effectiveness of Age-Specific Screening Intervals for People With Family Histories of Colorectal Cancer

Abstract

Background & aims: Relative risk of colorectal cancer (CRC) decreases with age among individuals with a family history of CRC. However, no screening recommendations specify less frequent screening with increasing age. We aimed to determine whether such a refinement would be cost effective.

Methods: We determined the relative risk for CRC for individuals based on age and number of affected first-degree relatives (FDRs) using data from publications. For each number of affected FDRs, we used the Microsimulation Screening Analysis model to estimate costs and effects of colonoscopy screening strategies with different age ranges and intervals. Screening was then optimized sequentially, starting with the youngest age group, and allowing the interval of screening to change at certain ages. Strategies with an incremental cost effectiveness ratio below $100,000 per quality-adjusted life year were considered cost effective.

Results: For people with 1 affected FDR (92% of those with a family history), screening every 3 years beginning at an age of 40 years is most cost effective. If no adenomas are found, the screening interval can gradually be extended to 5 and 7 years, at ages 45 and 55 years, respectively. From a cost-effectiveness perspective, individuals with more affected FDRs should start screening earlier and at shorter intervals. However, frequency can be reduced if no abnormalities are found.

Conclusions: Using a microsimulation model, we found that for individuals with a family history of CRC, it is cost effective to gradually increase the screening interval if several subsequent screening colonoscopies have negative results and no new cases of CRC are found in family members.

Keywords: Colon Cancer; Cost-Effectiveness Analysis; Genetic Risk Factor; Inherited; Relative Risk (RR).

Figure 1.

Sequential optimization method, for an example of individuals with one affected FDR (corresponds with the first row in Table 4). First, the optimal start age and interval for the youngest cohort (30-year-olds) is determined. The resulting screening ages between ages 30 and 44 are assumed as prior screening for the 45-year-olds, for whom the screening interval from age 45 is optimized. The screening ages until age 49 are then incorporated in the prior screening for 50-year-olds, and so on. For 70-year-olds, the optimal end age of screening is determined. In the figure, the derivation of an optimal screening strategy is given in these subsequent steps (indicated by the black arrows).