Cost-effectiveness of Prostate Radiation Therapy for Men With Newly Diagnosed Low-Burden Metastatic Prostate Cancer

IMPORTANCE: Prostate radiation therapy (PRT) is a treatment option in men with low-volume metastatic prostate cancer based on the results of the Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy Arm H (STAMPEDE-H) trial. However, the cost-effectiveness of this treatment remains unaddressed. OBJECTIVE: To assess the cost-effectiveness of PRT when added to androgen deprivation therapy (ADT) for men with low-volume metastatic hormone-sensitive prostate cancer (mHSPC). DESIGN, SETTING, AND PARTICIPANTS: This economic evaluation used microsimulation modeling to evaluate the cost-effectiveness of adding PRT to ADT. A simulated cohort of 10 000 individuals with low-volume mHSPC was created. Data from men with low-volume mHSPC were extracted and analyzed from January 18, 2019, through July 4, 2020. Transition probabilities were extracted from the STAMPEDE-H study. Health states included stable disease, progression, second progression, and death. Individual grade 2 or higher genitourinary and gastrointestinal toxic events associated with PRT were tracked. Univariable deterministic and probabilistic sensitivity analyses explored uncertainty with regard to the model assumptions. Health state utility estimates were based on the published literature. EXPOSURES: The combination of PRT and ADT using regimens of 20 fractions and 6 weekly fractions. MAIN OUTCOMES AND MEASURES: Outcomes included net quality-adjusted life-years (QALYs), costs in US dollars, and incremental cost-effectiveness ratios. A strategy was classified as dominant if it was associated with higher QALYs at lower costs than the alternative and dominated if it was associated with fewer QALYs at higher costs than the alternative. RESULTS: For the base case scenario of men 68 years of age with low-volume mHSPC, the modeled outcomes were similar to the target clinical data for overall survival, failure-free survival, and rates of PRT-related toxic effects. The addition of PRT was a dominant strategy compared with ADT alone, with a gain of 0.16 QALYs (95% CI, 0.15-0.17 QALYs) and a reduction in net costs by $19 472 (95% CI, $23 096-$37 362) at 37 months of follow-up and a gain of 0.81 QALYs (95% CI, 0.73-0.89 QALYs) and savings of $30 229 (95% CI, $23 096-$37 362) with lifetime follow-up. CONCLUSIONS AND RELEVANCE: In the economic evaluation, PRT was a dominant treatment strategy compared with ADT alone. These findings suggest that addition of PRT to ADT is a cost-effective treatment for men with low-volume mHSPC.