Cost-effectiveness analysis of endocrine therapy alone versus partial-breast irradiation alone versus combined treatment for low-risk hormone-positive early-stage breast cancer in women aged 70 years or older

Purpose: We performed a cost-effectiveness analysis of three strategies for the adjuvant treatment of early breast cancer in women age 70 years or older: an aromatase inhibitor (AI-alone) for 5 years, a 5-fraction course of accelerated partial-breast irradiation using intensity-modulated radiation therapy (APBI-alone), or their combination. Methods: We constructed a patient-level Markov microsimulation from the societal perspective. Effectiveness data (local recurrence, distant metastases, survival), and toxicity data were obtained from randomized trials when possible. Costs of side effects were included. Costs were adjusted to 2019 US dollars and extracted from Medicare reimbursement data. Quality-adjusted life-years (QALY) were calculated using utilities extracted from the literature. Results: The strategy of AI-alone ($12,637) was cheaper than both APBI-alone ($13,799) and combination therapy ($18,012) in the base case. All approaches resulted in similar QALY outcomes (AI-alone 7.775; APBI-alone 7.768; combination 7.807). In the base case, AI-alone was the cost-effective strategy and dominated APBI-alone, while combined therapy was not cost-effective when compared to AI-alone ($171,451/QALY) or APBI-alone ($107,932/QALY). In probabilistic sensitivity analyses, AI-alone was cost-effective at $100,000/QALY in 50% of trials, APBI-alone in 28% and the combination in 22%. Scenario analysis demonstrated that APBI-alone was more effective than AI-alone when AI compliance was lower than 26% at 5 years. Conclusions: Based on a Markov microsimulation analysis, both AI-alone and APBI-alone are appropriate options for patients 70 years or older with early breast cancer with small cost differences noted. A prospective trial comparing the approaches is warranted.