Growing teratoma syndrome: Is it a subtype of germ-cell tumors or another entity?

Abstract

e16040 Background: Growing teratoma syndrome(GTS ) is a process presenting with growing masses despite normal tumor marker levels(TML) after chemotherapy in non-seminomatous germ cell tumors (NSGCT). Methods: GTS patients between 2000-2016 were evaluated for clinicopathological features and survival outcomes retrospectively. Results: 17 (6,4%) of 266 NSGCT had GTS. Median follow-up was 57.7 ( 13.8-132.7) months. Median age 27 (17-51) years . Most (n = 14) of them had mixed germ-cell tumors & 12 had mature/immature teratoma in primary pathology at diagnosis. Most (n = 11) of them had stage 3 disease & 10 had high TML (S1-3). 11 GTS patients had good risk NSGCT. All (n = 17) had 4 BEP(bleomycin, etoposide, cisplatin) cycles. Recurrence occured in retroperitoneum (n = 13), lung (n = 3) & brain (n = 1). They were considered as GTS since they had normal TML despite growing masses. 5 patients were referred to surgery without salvage chemotherapy and they had teratoma on postoperative surgery. 13 had surgery after salvage chemotherapy (TIP: taxane, ifosfamide, platin) but 4 had unresectable disease and they had clinical benefit with interferone α2b. Two operated patients had diffuse necrosis on pathology whereas others had documented teratoma. Median DFS was 12.3 ( 5.7-18.8) months whereas median OS was 64.8 (15.5-158) months. 3 patients had no recurrence after surgery for GTS. 9 had salvage chemotherapy (gemcitabine/oxaliplatin, TIP) for NSGCT metastatic lesions with TML elevation and 2 of them had autolog stem cell transplantation. Conclusions: GTS is rare in NSGCT, but it should be considered in NSGCT patients with both growing masses & normal TML after primary treatment approach. GTS patients surgery with resectable masses should be referred to surgery since teratoma without viable tumor seems to have less benefit from chemotherapy and/or radiotherapy. Interferon α2b might be an option in unresectable GTS.