Management of relapsed stage I seminomatous germ cell tumor with retroperitoneal or pelvic only relapse.

Abstract

630 Background: For patients (pts) with stage 1 seminomatous germ cell tumor (SGCT) on active surveillance (AS), front-line therapy depends on the location and extent of relapse. We describe the characteristics and management of pts on AS with stage I SGCT with relapse in the retroperitoneum (RP) or pelvis only. Methods: The prospectively maintained Indiana University testicular cancer database was queried for pts with stage 1 SGCT on AS w/ RP or pelvic only relapse between 1990-2024. Pts were categorized into a chemotherapy, surgery, or radiation (XRT) group based on treatment at relapse. Comparisons between groups were done using Chi-square tests for categorical variables or Kuskal-Wallis test for continuous variables. Kaplan-Meier method was used to analyze progression-free survival (PFS) and overall survival (OS) using the log rank test to compare groups. Results: We identified 71 pts with stage 1 SGCT on AS w/ relapse in the RP or pelvis only. The median age at diagnosis was 37.2 yrs (range, 19.5-74.5). IGCCCG risk was good in all pts. At time of relapse, 37 pts (52.1%) were treated with chemo, 20 with surgery (28.2%), and 14 (19.7%) with XRT. The median time to relapse on stage I AS for pts treated with chemo was 9.5 months (0.84-91.7) compared to 19.9 months (1.6-60.2) with surgery and 13.1 months (4.6-48.8) with XRT (p=0.13). Chemo regimens used were BEP X 3 (62.2%), EP X 4 (21.6%), BEP X 4 (2.7%) and other (13.5%). 68 pts (95.8%) relapsed in the RP; 3 (4.2%) relapsed in the pelvis only. All 9 pts with lymph node (LN) size >5 cm were treated with chemo. In the 32 pts with LN size <3 cm, 12 (37.5%) were treated with surgery, 12 (37.5%) with chemo, and 8 (25%) with XRT. 11 total pts (15.5%) relapsed after front-line therapy and thus required multimodality treatment. This included 8 (21.6%) in the chemo group who relapsed; 2 out of 8 required RPLND while 6 were treated with salvage or high dose chemotherapy. 1 patient (5%) in the surgery group relapsed and required chemotherapy. In the XRT group, 2 pts (14.3%) relapsed; 1 was treated with salvage chemo and 1 with surgery. With a median follow-up time of 3.03 yrs (0-14.8), the 2-yr PFS for pts treated with chemo was 73.8%, surgery was 95%, and XRT was 92.3% (p=0.14). 2-yr OS was 100% for all treatment groups (p=0.58). Conclusions: In pts on AS with stage I SGCT w/ RP or pelvic only relapse, there was no difference in survival outcomes based on front-line therapy received. In this cohort of pts carefully selected for RPLND, the majority were cured with single-modality therapy; most of these pts had RP lymph nodes <3cm with a longer median time to relapse while on AS.