Outcome and recurrence patterns of low-risk gonadal germ cell tumors in children and adolescents

Pediatric low-risk gonadal germ cell tumors (LR-GCTs) are typically managed with close surveillance following surgery alone. However, the patterns of relapse and prognostic factors for relapse remain insufficiently understood. We reviewed 72 patients under 19 years old diagnosed with low-risk ovarian (OGCT) or testicular (TGCT) GCT between May 27, 2014, and December 31, 2022, from the TGM13-observatory (EudraCT 2013-004039-60). Among 30 OGCT (median age 13 years), 15 were dysgerminomas and 15 were non-dysgerminomatous OGCT (NDOGCT), with 10 patients having incomplete abdominal staging. Eleven relapses were observed, nine of which were locoregional. The three-year progression-free survival (PFS) was 73 % (95 % CI: 44–89) for dysgerminomas and 53 % (95 % CI: 26–74) for NDOGCT (p = 0.22). Among the 42 testicular tumors (median age 3 years), all but one were NSGCTs. Ten relapses occurred, resulting in one death. The three-year PFS for testicular GCTs was 76 % (95 % CI:59–86). Relapse patterns differed by age: in toddlers, relapses predominantly occurred in the lungs, while in adolescents, relapses were primarily in the para-aortic lymph nodes. The median time to relapse was six months. No significant prognostic factors for relapse were identified, including older age (>11 years), incomplete staging for OGCT, and the presence of lymphovascular invasion or embryonal carcinoma for TGCT. Survival after relapse remains excellent, and further research with a larger sample of children is needed to better identify risk factors for relapse in pediatric LR-GCTs.