Impact of 18F-DCFPyL-PSMA PET/CT on Radiotherapy Planning and Treatment Intensification in Occult Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy.

Abstract

Biochemical recurrence (BCR) after radical prostatectomy (RP) frequently occurs despite negative conventional imaging, making salvage treatment decisions challenging. We evaluated the impact of 18F-DCFPyL-PSMA PET/CT on disease detection and radiotherapy planning in patients with occult BCR.MethodsWe conducted a prospective single-center observational study including 85 patients with BCR after RP, negative or inconclusive conventional imaging, and PSA levels between 0.2 and 1.0 ng/mL or persistent PSA after previous local treatment. Detection rates (DRs) were evaluated according to PSA level, PSA doubling time (PSA-DT), and International Society of Urological Pathology (ISUP) grade. Changes in radiotherapy planning and treatment intensification were assessed by comparing intended management before and after PSMA PET/CT.ResultsPSMA PET/CT detected recurrent disease in 53% of patients. DRs increased significantly with PSA level, reaching 31.3% for PSA 0.2-0.5 ng/mL, 60.0% for PSA 0.5-0.9 ng/mL, and 77.8% for PSA 1.0 ng/mL (p Conclusions18F-DCFPyL-PSMA PET/CT provides clinically meaningful information beyond disease detection by substantially modifying radiotherapy planning and treatment selection in patients with occult BCR after RP. These findings support the integration of molecular imaging into salvage treatment planning to enable more personalized, biology-driven radiotherapy strategies.