Surveillance after complete response (CR) to first-line chemotherapy (chemo) in non-seminomatous germ-cell tumor (NSGCT).

Abstract

599 Background: Management of NSGCT following CR after first-line chemo remains variable across institutions. Recent data indicates that patients (pts) with teratoma and/or yolk sac tumor (YST) in their orchiectomy specimen were associated with finding teratoma or viable non-teratomatous GCT at post-chemo retroperitoneal lymph node dissection (PCRPLND) specimen. It is not clear whether this finding impacts long-term survival outcomes. We sought to evaluate long-term outcomes of surveillance after CR at Indiana University (IU) specifically in this patient population. Methods: We retrospectively reviewed the IU GCT database (January 1990-June 2024). Eligible pts were diagnosed with metastatic testicular/retroperitoneal NSGCT who achieved CR after first-line chemo defined by no residual mass >1cm in the longitudinal axis. Pts who were treated with chemo outside IU were excluded to reduce referral bias. Pts were stratified according to orchiectomy specimen into two groups: Those with teratoma and/or YST and those without either component. Primary outcomes were to estimate progression-free survival (PFS) and overall survival (OS) in these subgroups using Kaplan-Meier methodology. Results: A total of 261 pts met the inclusion criteria. Of these, 21 (8.0%) had teratoma, 50 had YST (19.2%), and 65 had both (24.9%). IGCCCG risk was good in 85.1%, intermediate in 6.1%, and poor in 8.8%. Median follow-up was 4.97 years (range, 0.01-28.80). Pre-chemo retroperitoneal lymph node size was <1 cm in 19 (7.3%), 1-3cm in 102 (39.1%), >3cm in 67 (25.7%), and unknown in 73 (28.0%). Four-year PFS for pts with teratoma or YST in their orchiectomy specimen was 92.2% vs 95.3% in pts without teratoma/YST (P=0.37). Four-year OS for pts with teratoma/YST in orchiectomy specimen was 98.0% vs 98.1% in pts without teratoma/YST (P=0.59). Late relapse occurred in 3.7% (n=5) of those with teratoma/YST and 2.4% (n=3) for those with neither (P=0.72). Of the 16 pts who relapsed, 8 underwent delayed RPLND, 3 received salvage chemo, 2 were treated with salvage chemo and RPLND, and 3 underwent resection of other metastatic sites. At last follow-up, 12 pts who relapsed were without evidence of disease, 2 were alive with disease, and 2 died of NSGCT. Conclusions: In this large cohort, most pts with NSGCT who achieved CR after first-line chemo remained disease-free on surveillance, regardless of the presence of teratoma or YST in the orchiectomy specimen. Relapses were uncommon and most pts who relapsed were salvaged successfully with surgery and/or chemo. Group Progression Count Row N % Late Relapse Count Row N % Any Teratoma (86) 7 8.1 % 3 3.5 % Any YST (115) 10 8.7 % 5 4.3 % Both Present (65) 6 9.2 % 3 4.6 % Either Present (136) 11 8.1 % 5 3.7 % Neither Present (125) 5 4.0 % 3 2.4 % P-value a 0.17 P-value a 0.72 a P -values compare “Either Present” vs “Neither Present.”