Cost Effectiveness of Prostate Boost with High-Dose Rate Brachytherapy Versus Intensity Modulated Radiation Therapy in the Treatment of Intermediate-High Risk Prostate Cancer

Abstract

The recently published ASCENDE-RT randomized clinical trial demonstrated improved biochemical control, albeit with increased toxicity, for a prostate boost with brachytherapy versus external beam radiation therapy alone. Our single-institution retrospective review demonstrated similar findings. It is unknown whether the increased biochemical control of a prostate brachytherapy boost outweighs its increased cost and toxicity. In this study, we investigated the cost-effectiveness of these two modalities in the treatment of intermediate-high risk prostate cancer. A multi-state Markov decision tree was created to model a patient with intermediate-high risk prostate cancer. The two treatment options modeled were: (1) 23 fractions of IMRT and 2 fractions of HDR prostate brachytherapy (brachytherapy boost), and (2) 44 fractions of IMRT (IMRT alone). Each patient received 1 year of hormone therapy, per the ASCENDE-RT protocol. Model assumptions, including clinical outcomes, toxicity, and utilities were obtained from the medical literature. Costs were estimated using Medicare reimbursement data. The expected lifetime costs and quality-adjusted life years (QALY) were then estimated. If applicable, an Incremental Cost-Effectiveness Ratio (ICER) was computed. One-way sensitivity analyses were performed over a range of cancer progression rates, utilities, and cost assumptions. We assumed a maximum willingness to pay of $50,000/QALY. The estimated expected lifetime costs of brachytherapy boost were $71,978, compared to $81,543 for IMRT alone. While having a higher upfront cost, brachytherapy boost reduced expected lifetime costs because it decreased the incidence of metastatic castration-resistant prostate cancer (mCRPC), cutting the use of expensive targeted therapy for mCRPC. Brachytherapy boost had an expected QALY of 11.20 years, compared to 9.1 years for IMRT alone. Therefore, brachytherapy boost is a dominant treatment strategy over IMRT alone. One-way sensitivity analyses found brachytherapy boost to be cost-effective over a range of cost, utility, and cancer progression rate assumptions. IMRT with HDR brachytherapy boost is a cost-effective treatment for intermediate-high risk prostate cancer compared to IMRT alone.