1487 PERSISTENT PROSTATE CANCER IN PATIENTS TREATED WITH PROSTATE RADIOTHERAPY WHO SUBSEQUENTLY UNDERGO RADICAL CYSTOPROSTATECTOMY FOR BLADDER CANCER

INTRODUCTION AND OBJECTIVES: Half of men with prostate cancer (PCa) will choose radiotherapy (RT) for treatment. A prostate biopsy is not routinely performed after RT as a recurrence is determined by elevated PSA. We sought to determine the incidence of persistent PCa in patients who received definitive RT for PCa and subsequently developed bladder cancer necessitating radical cystectomy (RC). METHODS: We identified 78 men who underwent RC for bladder cancer between 1993 and 2012 at our center who had a previous history of PCa treated with RT between 1986 to 2010. A biochemical recurrence (BCR) before surgery was identified by the treating physician, PSA greater than 2 ng/ml or the administration of androgen deprivation therapy (ADT). All pathologic specimens were evaluated by a genitourinary pathologist. RESULTS: Of the 78 men who underwent RC the median time from radiotherapy was 77 months (IQR 38-118) with only 12 patients undergoing RC less than 30 months from radiation treatment. External beam radiotherapy (EBRT) was performed in 35 men (45%), while 12 men received brachytherapy (15%) and 24 (31%) receiving both EBRT and brachytherapy and 6 (14%) received unknown radiation dose or type. For those men undergoing EBRT, the median dose of radiation was 7020 cGY. One in three men had a history of ADT and 21% had a known BCR prior to RC. PSA values were available for 62 men prior to RC (80% of patients). The median PSA prior to RC was 0.95 (IQR 0.06-2.11) with 24% of patients having a PSA of 2 ng/ml or greater. The rate of histologic gradable prostate cancer was 45% at RC with 10% having ungraded PCa, 14.1% Gleason 6 or less, 18% Gleason 7 and 13% Gleason 8 or higher. Prostate lymph node metastasis were found in four men (5%) associated with Gleason 8 (2 men) and 9 (2 men) tumors. The prostate surgical margins were positive in 8 (10%) with 11.5% pT3b or greater. When grouped by time of radiotherapy, the prevalence of PCa was 100% before 1980 (4/4), 67% between 1980 and 2000 (33/49), and 24% since 2000 (6/25) (p 0.0001). Of those patients with persistent PCa, 11% received brachytherapy, 70% received EBRT and 19% received both EBRT and brachytherapy (p 0.001). CONCLUSIONS: In our series of men undergoing RC after RT, 45% of men had persistent gradable PCa with a decrease in PCa rates associated with later years of treatment and the combined brachytherapy/EBRT modality. These findings are consistent with higher radiation dose levels administered in the more recent era of treatment. The prostate should be treated with similar oncologic attention during the RC in men with prior radiation treatment.