Does variation in either age at start of therapy or duration of therapy make chemoprevention with finasteride cost-effective?

Background: Incremental cost-effectiveness ratios (ICERs) of finasteride for prostate cancer prevention are consistent with estimates beyond $100 000 per quality-adjusted life-year (QALY). The majority of these analyses are based on chemoprevention starting in men aged 50–55 years. We sought to evaluate the impact of varying both age at commencement of therapy and length of therapy on the cost-effectiveness of finasteride. Methods: A probabilistic Markov model was designed to estimate lifetime prostate health-related costs and quality-adjusted survival for men receiving or not receiving chemoprevention with finasteride. ICERs across scenarios varying age at start of therapy and duration of chemoprevention were compared. Results: The ICER for men starting chemoprevention at age 50 and continuing to age 75 was $88 800 per QALY when assuming finasteride causes a constant risk reduction across all tumor grades (base case 1) and $142 300 per QALY when assuming a differential treatment effect according to Gleason score (base case 2). When starting age is increased, the ICERs trend downward and nadir at 65 years to $64 700 per QALY (base case 1) and $118 600 per QALY (base case 2). Altering duration of therapy had minimal impact. Patient-level experiences with finasteride and BPH significantly influenced the cost-effectiveness of chemoprevention. Conclusions: Initiating chemoprevention at ages when prostate cancer incidence is higher improves its cost-effectiveness profile. Only when assuming a constant risk reduction for all tumor grades, did finasteride fall below $100 000 per QALY, but this finding was not upheld when accounting for side effects associated with the drug.