Cost-effectiveness of metastasis-directed therapy in the setting of oligometastatic hormone-sensitive prostate cancer.

Abstract

147 Background: Androgen deprivation therapy (ADT) has historically been used as the backbone of treatment in patients with newly-diagnosed hormone-sensitive metastatic prostate cancer. However, recent literature has suggested the potential utility of metastasis-directed therapy (MDT) in a subset of patients with oligometastatic prostate cancer (OPC), potentially allowing for ADT-free survival. Methods: A cost-effectiveness analysis was performed comparing (1) ADT upfront versus (2) MDT followed by salvage ADT in patients with asymptomatic hormone-sensitive OPC. MDT was delivered via stereotactic body radiation therapy (SBRT) over 3 fractions. ADT consisted of Lupron injections every 3 months. Costs were calculated from a payor’s perspective based on Medicare CPT codes, CLAB fee schedule, and ASP drug prices. ADT-free survival was modeled based on results from STOMP trial; costs of retreatment were not considered in the MDT arm. Based on prior literature, health utility was assumed to be 0.9 without ADT, and 0.82 with ADT. Given paucity of long-term data on survival effect of MDT with delayed ADT, both arms were assumed to have identical long-term disease transition state probabilities. Results: Total cost of ADT upfront vs. MDT + salvage ADT was $3,430 vs. $9,434 at 1 year, and $10,289 vs. $13,806 at 3 years. Compared to ADT alone, MDT + salvage ADT showed improvements in quality-adjusted life years (QALYs) of 0.07 and 0.15 at 1 and 3 years respectively, translating to incremental cost-effectiveness ratio (ICER) of $85,385/QALY at 1 year and $24,118/QALY at 3 years. Conclusions: Using a willingness-to-pay ICER threshold of $100,000/QALY, MDT with SBRT is shown to be a cost-effective option compared to ADT alone in patients with OPC, particularly when utilizing a longer follow-up time period.