Cost-effectiveness of early colonoscopy surveillance after cancer resection

Short-interval surveillance colonoscopy at 1 year has been recently recommended following curative-intent surgery for colorectal cancer. However, the efficacy and cost-effectiveness of this endoscopic strategy is largely unknown.

To assess the clinical and economic impact of early surveillance post-surgical colonoscopy at 1 year in relation to the detection of metachronous colorectal cancer.

A decision analysis model was constructed in order to compare a strategy of 1-year endoscopic surveillance versus no early endoscopy following surgical resection for colorectal cancer. A 2-year cancer upstaging was modelled in order to simulate cancer progression in patients with metachronous colorectal cancer who were not referred to early endoscopy. Endoscopic prevalence of metachronous colorectal cancer was estimated from a previous pooled data analysis based on systematic review of the literature. Costs of colonoscopy and cancer care were estimated from Medicare reimbursement data. Outcome measures were the number of early colonoscopies needed to detect one case of cancer or to prevent one cancer-related death and the incremental cost-effectiveness ratio.

The number of early 1-year colonoscopies needed to detect one colorectal cancer and to prevent one colorectal cancer-related death was 143 and 926, respectively. The incremental cost-effectiveness ratio of the early 1-year colonoscopy as compared to a policy of not performing it was $40,313 per life-year gained. The incremental cost-effectiveness ratio of performing early surveillance colonoscopy was sensitive to the changes in cancer prevalence. However, only a reduction from the baseline value of 0.7% to 0.19% was associated with an incremental cost-effectiveness ratio higher than $150,000. Other assumptions about cancer upstaging, initial distribution of cancer, and costs had a lesser influence on incremental cost-effectiveness ratio differences.

Our study shows that the recently recommended short-interval 1-year surveillance colonoscopy following colorectal cancer resection is a clinically efficient and cost-effective strategy in terms of cancer detection and cancer-specific death prevention.