Prostate-specific antigen flare induced by 223 RaCl 2 in patients with metastatic castration-resistant prostate cancer

摘要

Purpose Prostate-specific antigen (PSA) flare is a well-known phenomenon in patients with prostate cancer, but its impact during radium-223 dichloride (_(223)RaCl~(2)) therapy is still unclear. This radioisotope has shown to improve overall survival in metastatic castration-resistant prostate cancer (mCRPC). We sought to evaluate the impact of PSA flare on survival and its relation with metabolic parameters on_(18)F-labeled sodium fluoride PET/CT. Methods We conducted a retrospective study of 168 patients with mCRPC (median age 69; median PSA 29.7) receiving_(223)RaCl~(2). Overall survival (OS) and progression-free survival (PFS), estimated by the Kaplan–Meier method and compared using a log-rank test, were evaluated for patient groups corresponding to different definitions of PSA flare. Metabolic_(18)F-fluoride PET/CT data were analyzed as well. Results Immediate PSA decline was observed in 49 patients (29.2%), whereas no PSA response was observed in 59 patients (35.1%). PSA flare (defined as rise after the first cycle followed by decrease below the baseline) was observed in 20 patients (11.9%) and PSA flare followed by a decrease from peak but not below baseline was observed in 40 (23.8%). The first flare subgroup had a median PFS and OS of 20.8 and 23.9?months, respectively. These outcomes were not significantly different from patients with immediate PSA decrease, but were significantly better than in patients with persistent PSA elevation (3.1?months for PFS and 11.5?months for OS, p ?