Cost-effectiveness of endocrine therapy versus radiotherapy versus combined endocrine and radiotherapy for older women with early-stage breast cancer

Purpose: To evaluate the cost-effectiveness of endocrine therapy (ET), radiation therapy (XRT), and combination ET + XRT as post-surgical treatment for older women with early-stage breast cancer from the societal perspective. Methods: We constructed a Markov state-transition model consisting of three mutually exclusive health-states:Disease-Free, Recurrence, or Death. Osteoporotic fracture, radiation-induced breast fibrosis, and radiation pneumonitis were modeled as treatment-related adverse events (AEs). Cancer registry-linked-Medicare data were used to assess probability of recurrence and total costs, after propensity adjustment to account for treatment selection, among women aged > 65 years diagnosed with estrogen receptor positive or progesterone receptor positive (ER+/PR+) breast cancer receiving ET, XRT, or ET + XRT in 2007-2011. Following randomized controlled trials, overall survival was assumed equivalent, but locoregional recurrence varied. Indirect costs and health-state utilities were literature-driven and varied in sensitivity analyses. Costs and outcomes were discounted at 3% annually. Results: In a cohort of 10,000 women over ten years, we estimated 1620 total recurrences in the ET-only group, 1296 in the XRT-only group, and 1076 with ET + XRT. Compared to ET-only, the base-case incremental costeffectiveness ratio (ICER) was $10,826 per quality-adjusted life-year (QALY)-gained for XRT-only and $26,834/ QALY-gained for ET + XRT. Similarities in cost and effectiveness between treatments led to highly sensitive results. We also present clinically-relevant patient preference scenarios for recurrence risk-averse patients and near-term AE risk-averse patients. Conclusions: The cost-effectiveness of regimens including ET and/or XRT in older women with early-stage breast cancer is sensitive to small differences in costs, as well as risk of, and utilities associated with, locoregional recurrence, suggesting that patient preferences concerning treatment benefits and risks should be considered by physicians. (c) 2021 Elsevier Ltd. All rights reserved.