Cost-utility analysis of screening high-risk groups for anal cancer

Objectives Cost-utility analysis of screening for anal cancer in high-risk groups from a UK perspective. Methods Criteria for the assessment of screening programmes were combined in a Markov model representing the natural history of anal cancer and HIV infection in the UK population of men who have sex with men (MSM). Alternative screening programmes were overlaid on the natural history model to evaluate their impact. The model was populated using data derived from a systematic review of the literature, and calibrated probabilistically to represent joint uncertainty in the input parameters. Results Reference case results showed screening is unlikely to be cost-effective. Sensitivity analyses identified two important parameters: regression from low-grade anal intra-epithelial neoplasia (AIN) and utility effects. Increased AIN regression rates resulted in a minimum incremental cost per QALY gained of pound 39 405, whereas a best case scenario reduced the ratio to pound 20 996. Conclusions There are major areas of uncertainty. New analyses of existing primary data, undertaken specifically to inform regression rates may usefully update key parameters at little additional cost. If these analyses increase the likelihood that screening is cost-effective, further studies of the utility effects of treatment for high-grade AIN, and potential screening attendance rates may be justified.