Radium-223-Dichloride in Castration Resistant Metastatic Prostate Cancer—Preliminary Results of the Response Evaluation Using F-18-Fluoride PET/CT

The purpose of this study was to evaluate the outcome after Radium-223-dichloride ((223)RaCl(2)) treatment of patients with skeletal metastases of castration resistant prostate cancer using whole-body (18)F-Fluoride PET/CT. Sodium (18)F-fluoride [(18)F]-NaF PET/CT was performed prior the treatment of (223)RaCl(2), after the first cycle and after the sixth cycle. The skeletal metastases were analyzed quantitatively using modified PET response evaluation PERCIST criteria. The patients were also analyzed for S-PSA. All ten patients responded in [(18)F]-NaF scans after 6 cycles, but interim analysis after the 1st cycle did not give additional information about the outcome. The S-PSA decrease correlated with [(18)F]-NaF response, only 1 patient demonstrated progressive disease, i.e., >25% increase in S-PSA values during (223)RaCl(2). Our results (although preliminary) suggest that (18)F-Fluoride PET/CT is useful in the follow-up of castration resistant prostate cancer with skeletal metastases.