Patient characteristics and survival in primary prostate sarcomas: An analysis of the SEER database.

271 Background: Primary prostate sarcoma (PPS) is a rare neoplasm of prostate and is associated with poor survival outcome. Methods: We conducted an analysis of patients with PPS in the Surveillance, Epidemiology, End Results (SEER) database from year 2000 to 2020. Patients were identified by using the primary cancer site codes for prostate as well as histological codes (ICD-O-3) that matches the list of sarcoma histology found in the NCCN soft tissue sarcoma and bone cancer guidelines. Data for demographics, disease extent and median overall survival (OS) were obtained. Sarcomas mixed with carcinomas, so-called carcinosarcomas, were included in the analysis. OS data of prostate adenocarcinoma from same database were obtained for a comparison. Results: During the period analyzed, a total of 1,120,527 patients with primary prostate neoplasms were identified. Among them, 239 patients (0.0002%) had PPS. Majority were Caucasian (67.8%) followed by Hispanics (13.4%) and African Americans (8.8%). The most common histology was rhabdomyosarcoma (28.5%), followed by leiomyosarcoma (21.8%), carcinosarcoma (16.7%), and unspecified sarcomas (8.8%).Among 221 patients with known extent of disease, 29.4%, 37.1% and 33.5% had localized, locoregional and distant metastatic disease, respectively. Overall, PPS was associated with worse OS than prostate adenocarcinoma (28 months vs. 183 months, P<0.01). OS for patients with localized, regional, and distant diseases were 54, 39, and 18 months, respectively (P=0.04). Patients with carcinosarcomas had worse OS than those with pure sarcomas (15 months vs. 34 months, P<0.001). Among patients with locoregional disease, 19 (14.2%) received chemotherapy only, 84 (62.7%) received surgery only, and 31 (23.1%) received both chemotherapy and surgery. Median OS was not reached in those with locoregional disease who did not receive surgery while it was 44 months in those who received surgery (P=0.055). As for those with distant metastasis, 37 (56.1%) received chemotherapy only, 13 (19.7%) received surgery only, and 16 (24.2%) received both chemotherapy and surgery. Median OS for those with metastatic disease who received chemotherapy versus no chemotherapy was 9 months versus 19 months (P=0.063). Conclusions: PPS was rare and associated with worse survival outcome compared with prostate adenocarcinomas. Carcinosarcomas were less common than pure sarcomas and were associated with worse survival than pure sarcomas.