Cost effectiveness analysis of intensive versus conventional follow up after curative resection for colorectal cancer

Objective: To determine the cost effectiveness of intensive follow up compared with conventional follow up in patients with colorectal cancer. Design: Incremental cost effectiveness analysis recognising differences in follow up strategies, based on effectiveness data from a meta-analysis of five randomised trials. Setting: United Kingdom. Main outcome measures: Taking a health service perspective, estimated incremental costs effectiveness ratios for each life year gained for five trials and four trials designed for early detection of extramural recurrences (targeted surveillance). Results: Based on five year follow up, the numbers of life years gained by intensive follow up were 0.73 for the five trial model and 0.82 for the four trial model. For the five trials, the adjusted net (extra) cost for each patient was £2479 (€3550; $4288) and for each life year gained was £3402, substantially lower than the current threshold of NHS cost acceptability (£30 000). The corresponding values for the four trial model were £2529 and £3077, suggesting that targeted surveillance is more cost effective. The main predictor of incremental cost effectiveness ratios was surveillance costs rather than treatment costs. Judged against the NHS threshold of cost acceptability, the predicted incremental cost threshold was ninefold and the effectiveness threshold was 3%. Conclusions: Based on the available data and current costs, intensive follow up after curative resection for colorectal cancer is economically justified and should be normal practice. There is a continuing need to evaluate the efficacy of specific surveillance tools: this study forms the basis for economic evaluations in such trials.