LAUSR

534 Background: RPLND as first-line treatment for testicular seminoma is less well defined than for testicular nonseminomas. Furthermore, RPLND performed in the post-chemotherapy (PC) setting for seminoma patients with a PET avid residual mass > 3 cm can be technically challenging. We describe utilization of RPLND in the primary and PC settings and report on overall survival rates following surgery for these men. Methods: Using 2004-2014 data from the National Cancer Database, we identified 62,727 men with 1° testicular cancer, of which 31,068 men were diagnosed as having seminoma. After excluding men with benign, non-germ cell, and nonseminoma histologies, those who did not undergo RPLND, and those whose clinical stage (CS) or survival data were unavailable, 412 men comprised our final cohort. Men were further stratified according to whether they had 1° RPLND vs PC-RPLND, with 1° RPLND defined as RPLND performed for CS IA-IIB without prior chemotherapy, and PC-RPLND classified as RPLND performed for CS IIA-IIIC after chemotherapy. Descriptive statistics were used to summarize clinical and demographic factors. The Kaplan-Meier method was used to determine overall survival. Results: From 2004-2014, 412 men with testicular seminoma underwent RPLND, of which 89% and 11% were in the 1° and PC settings, respectively. There were no significant differences in clinical or demographic characteristics when comparing men in these 2 groups. The majority of men with testicular seminoma undergoing PC-RPLND were treated at an academic center (63.8%) or comprehensive community cancer program (21.3%). The median follow-up was 4.1 years. Of 372 patients with available survival data, five-year overall survival was 94.2% and 89.0% in the 1° RPLND and PC- RPLND groups, respectively. Conclusions: Though RPLND is rarely used as 1° therapy in testicular seminoma, overall survival rates appear to be excellent, as they do for men with testicular seminoma after PC-RPLND. Ongoing trials evaluating the use of RPLND for early metastatic, low-volume disease will clarify its role in the management of testicular seminoma.