Laying the groundwork for future health economic evaluation of [18F]PSMA PET/CT in guiding treatment decisions for metastatic castration-resistant prostate cancer patients.

INTRODUCTION: Recent study results of our group demonstrated that [18F]PSMA-1007 (PSMA) PET/CT outperforms PSA response in predicting overall survival in metastatic castration-resistant prostate cancer (mCRPC) patients. However, its health economic implications for guiding treatment decisions remained unclear. This post-hoc analysis explores the potential impact of PSMA PET/CT on treatment decisions and patient-level costs, highlighting its relevance for future health economic evaluations. METHODS: Time from therapy initiation to therapy discontinuation and the reasons for discontinuation were studied. A swimmer plot visualised individual patient timelines and censored events. Hospital-perspective cost estimates were determined per patient. RESULTS: Among 60 patients, 53 discontinued therapy: 28 due to disease progression, 7 due to toxicity, and 18 after completing chemotherapy cycles. Seven patients remained on-treatment at the time of analysis. Costs varied by treatment duration and medication: monthly hospital costs were €1,826 for abiraterone, €3,652 for enzalutamide and €3,190 for chemotherapy. The cost of PSMA PET/CT was estimated at €1,286 and requires contextual evaluation within rapidly changing treatment pathways. DISCUSSION: PSMA PET/CT helps inform treatment decisions, but its cost is considerable relative to the cost of conventional therapy. Whether the use of PSMA PET/CT translates into avoidance of ineffective therapy or in therapy-related cost savings should be studied in formal cost-effectiveness analysis. Cost savings are less evident where conventional treatment costs are low compared with novel (but costly) targeted therapy options. Standardised imaging protocols, multicentre data and population registries are essential to strengthen the evidence base and enable future health economic evaluation.