Patterns of progression in bone and soft tissue following treatment with Ra-223 in metastatic castrate resistant prostate cancer (mCRPC).

222Background: Bone scans were not obtained in the phase 3 ALSYMPCA trial, and retrospective series have reported varying rates of development of new lesions and resolution of existing lesions, following treatment with Radium-223 (Ra-223). Methods: We performed a retrospective chart review of all men with mCRPC who received at least one dose of Ra-223 at Duke Cancer Institute from June 1, 2013 to June 1, 2015, in order to specifically describe radiographic changes on bone scan and CT during and following treatment. Radionuclide bone scans were reviewed by two radiologists prior to, during, and following Ra-223 treatment. The automated bone scan index (aBSI) was generated at each time point using EXINI boneBSI v. 2. Results: We identified 61 men with mCRPC (72% white, 28% black, median age 70) who received ≥ 1 dose of Ra-223 (median 5 doses, range 1-6). Prior treatments included: abiraterone (71%), enzalutamide (71%), sipuleucel-T (59%), docetaxel (56%), and cabazitaxel (18%). At baseline, 46% of men had n...