5020 Background: The importance of local treatment in oligometastatic prostate cancer (OPC) is unknown. Stereotactic ablative radiotherapy (SABR) is highly focused, high-dose radiation that is well suited for treatment of oligometastases. Here we report on the safety and preliminary clinical outcomes of SABR in a modern cohort of OPC men. Methods: Eighty four men who satisfied criteria of OPC diagnosed on imaging underwent consolidative SABR were then followed prospectively on our IRB approved registry by our GU multidisciplinary team. We collected demographic, clinical, toxicity and efficacy information. We examined the first 66 men in this preliminary report to allow for a minimum of 4.5 months follow-up. SABR was delivered in 1-5 fractions of 5-18 Gy. Kaplan-Meier method was used to assess local progression-free survival (LPFS), biochemical progression-free survival (bPFS; PSA nadir+2), distant progression free survival (DPFS), ADT-free survival (ADT-FS) and time-to-next intervention (TTNI). Results: Of the 66 OPC patients analyzed, 25 (38%) men presented as synchronous OPC and the remaining 41 had recurrent OPC. Median and mean follow-up was 61 and 66 weeks, respectively. Patient and disease factors as listed in the Table. Crude Grade 1 and 2 acute toxicities were 36% and 11%, respectively, with no Grade > 2 toxicity. SABR was delivered to 134 metastases: 89 bone (66%), 40 nodal (30%) and 5 (4%) visceral metastases. Overall LPFS at 1-year was 92%. The bPFS and DPFS at 1-year were 69% and 69%, respectively. Median TTNI was not reached yet. Of the 18 men with hormone sensitive prostate cancer who had their ADT deferred, 11/18 (56%) remain free of disease following SABR (1-year ADT-FS was 78%) and in 17 castration resistant men, 11 had > 50% PSA declines with 1-year TTNI of 30% with a median of 45 weeks. Conclusions: Consolidative SABRfor OPCis feasible and well tolerated. The preliminary clinical outcomes in our series is limited by heterogeneity and size but our data suggests that this approach is worthy of further prospective study. [Table: see text]
810: Bicalutamide 150 MG Alone or as Adjuvant to Standard Care Significantly Improves Progression-Free Survival in Patients with Early, Non-Metastatic Prostate Cancer (Median 5.4 Years' Follow-Up)
