Cost-Effectiveness Analysis of CT Colonography for Colorectal Cancer Screening Program to Working Age in Japan

To assess the cost-effectiveness of computed tomography colonography (CTC) for a colorectal cancer screening program in a working population (aged 40-60 years) from a health care payer's perspective in Japan.

A Markov model for colorectal cancer was constructed to estimate the long-term (10-year, 20-year, and 30-year) effect of introducing CTC for three different strategies in the cohort aged 40 years on April 1, 2011. Strategy 1 (the current strategy in Japan): fecal occult blood test (FOBT) followed by optical colonoscopy (OC). In this case, 41.8% of those who were FOBT-positive did not undergo OC (uptake 58.2%). Strategy 2: All FOBT-positive cases would be offered CTC (uptake 79.1%) followed by OC. Strategy 3: Only those FOBT-positive cases who were reluctant to undergo OC (41.8%) would be offered CTC (assumed uptake 50.0%) followed by OC. Epidemiological data were obtained mainly from statistics published by the Japanese National Cancer Center. We set quality-adjusted life-year (QALY) as the primary outcome and colorectal cancer death and expected life-years as secondary ones. The discount rate for both costs and outcomes was set at 3%.

In the base-case (20-year) analysis, total cost was increased from Japanese yen (JPY) 65,614 million (strategy 1) to JPY 69,405 million (strategy 2) but was decreased to JPY 63,878 million (strategy 3). The total QALY increased from 28,156,046 QALYs (strategy 1) to 28,158,349 (strategy 2) and 28,159,058 QALYs (strategy 3). Therefore, the incremental cost-effectiveness ratio was JPY 1,646,000 per QALY gained for strategy 2 and strategy 3 was dominant against strategy 1, both of which were well below the Japanese threshold (JPY 5-6 million per QALY gained).

Adding CTC into the current colorectal cancer screening program for the working population seems to be a cost-effective option.