COST EFFECTIVENESS OF ACCELERATED PARTIAL BREAST RADIOTHERAPY VERSUS WHOLE BREAST RADIOTHERAPY: IMPACT OF INCLUDING PATIENT PERSPECTIVE

Purpose: To assess the cost effectiveness of new accelerated partial breast radiotherapy (RT) modalities compared to standard whole breast RT (WBRT), which may be delayed in the community setting. Accelerated strategies (three-dimensional conformal external-beam RT (3D-CRT) and brachytherapy with balloon catheter) ease time and toxicity burdens of WBRT, requiring treatment 2 times/day for 5 days instead of daily for 4-7 weeks, and may deliver RT more efficiently to the tumor bed, where most breast recurrences occur; however, long-term trial evidence is unavailable.

Method: Decision analytic Markov models from the payer and payer+patient perspectives were created to evaluate 4 RT strategies following breast-conserving surgery for Stage I breast cancer: standard WBRT, WBRT delayed by 8+ weeks, 3D-CRT, and brachytherapy. The microsimulation included 10,000 hypothetical 60yo women for 15 years follow-up. Data were from published studies, US life tables, SEER data, and Medicare reimbursement rates (2008US$). Costs and QALYs were discounted at 3%. In the base case we assumed equivalent utility for all RT options (0.92) and equivalent efficacy between accelerated strategies. Assumptions were varied in sensitivity analyses. The model is validated for the WBRT strategy based on pooled trial data on overall survival for the same population (via AdjuvantOnline!).

Results: From the payer perspective, standard WBRT is the dominant strategy (costing $11K and yielding 11.04 QALYs). When 3D-CRT’s utility is 1% higher than standard WBRT, the CE ratio for 3D-CRT is $53,900/QALY gained. When patient time/transportation costs are included, 3D-CRT is the preferred strategy at a willingness-to-pay threshold of $100K/QALY; traditional WBRT then costs $185,700/QALY gained. Brachytherapy-based RT and delayed WBRT are dominated by WBRT and 3D-CRT under all reasonable assumptions.

Conclusion: 3D-CRT appears to be a cost-effective RT modality to reduce the burden of standard WBRT with its high patient costs and lower utility. This is particularly important for individuals that receive delayed RT, who are more likely to be individuals of lower socioeconomic status and non-White race.