PURPOSE: Electron-beam boosts (EBB) are routinely added after conservative surgery and tangential radiation therapy (TRT) for early-stage breast cancer. We performed an incremental cost-utility analysis to evaluate their cost-effectiveness. METHODS: A Markov model examined the impact of adding an EBB to TRT from a societal perspective. Outcomes were measured in quality-adjusted life years (QALYs). On the basis of the Lyon trial, the EBB was assumed to reduce local recurrences by approximately 2% at 10 years but to have no impact on survival. Patients’ utilities were used to adjust for quality of life. Given the small absolute benefit of the EBB, baseline utilities were assumed to be the same with or without it, an assumption evaluated by Monte Carlo simulation. Direct medical, time, and travel costs were considered. RESULTS: Adding the EBB led to an additional cost of $2,008, an increase of 0.0065 QALYs and, therefore, an incremental cost-effectiveness ratio of over $300,000/QALY. In a sensitivity analysis, the ratio was moderately sensitive to the efficacy and cost of the EBB and highly sensitive to patients’ utilities for treatment without it. Even if patients do value a small risk reduction, the mean cost-effectiveness ratio estimated by the Monte Carlo simulation remains high, at $70,859/QALY (95% confidence interval, $53,141 to $105,182/QALY). CONCLUSION: On the basis of currently available data, the cost-effectiveness ratio for the EBB is well above the commonly cited threshold for cost-effective care ($50,000/QALY). The EBB becomes cost-effective only if patients place an unexpectedly high value on the small absolute reduction in local recurrences achievable with it.
PRM138 A Propensity to Get It Right. A Monte Carlo Simulation Study Comparing Statistical Methods to Obtain Correct Cost-Effectiveness Estimates in Observational Studies
