Clinical outcomes in patients with post-chemotherapy residual non-retroperitoneal (RP) disease in non-seminomatous germ-cell tumors (NSGCT)

e17027 Background: In patients (pts) with metastatic NSGCT, the presence of teratoma in the primary tumor specimen or in the post-chemo RP lymph node dissection (RPLND) has previously been shown to have no impact on prognosis. We report clinical outcomes of pts based on pathology in primary tumor and from post-chemotherapy non-RP disease surgical resection. Methods: The prospectively maintained Indiana University testicular cancer database was queried for pts with metastatic NSGCT treated between 1990-2021 who completed first-line chemotherapy and had residual extra-RP disease in the absence of residual RP disease. Pts who had post-chemo non-RP surgical resection were included. Kaplan-meier methods were used to analyze progression-free survival (PFS) and overall survival (OS). Results: 131 pts met eligibility. Median age at diagnosis was 28.6 (range, 16.2-51.5). Primary site was testis in 130 pts (99%). Primary tumor predominant histology was embryonal (34.4%), mixed (26%), choriocarcinoma (14.5%), teratoma (11.5%), yolk sac (10.7%), seminoma (1.5%). Metastatic sites at diagnosis were lung (27.5%), brain (19.8%), RP (14.5%), liver (8.4%), mediastinal LN (7.6%), bone (7.6%). All pts with RP mets at diagnosis had normalization of RP nodes after chemo. All pts had surgical resection of non-RP disease. None had RPLND. IGCCCG risk was good in 56, intermediate in 23, and poor in 52 pts. Median pre-chemo AFP was 66.7 (0.9-467,000). hCG was 692 (0.5-500,000). First-line chemo was BEPX4 in 68, BEPX3 in 29, EPX4 in 10, VIPX4 in 8, and other in 16 pts. 76 pts (58%) had teratoma in the primary tumor. Median follow-up was 3.16yrs. 2-yr PFS for pts with teratoma in primary was 59% (95% CI 45-71) vs. 54% for pts without (95% CI 38-67); p = 0.42. 2-yr OS for pts with teratoma in primary was 85% (95% CI 73-92) vs. 70% for pts without (95% CI 54-81); p = 0.18. 2-yr PFS and OS based on pathology and location of non-RP site are listed in Table 1. Conclusions: The presence of teratoma in primary tumor and post-chemotherapy non-RP resections is not associated with worse PFS or OS in pts with metastatic NSGCT. [Table: see text]