EXTRARENAL NON-CEREBRAL MALIGNANT RHABDOID TUMOR IN CHILDREN: DOES MAINTENANCE CHEMOTHERAPY PLAY A ROLE IN SURVIVAL?

Introduction: Malignant rhabdoid tumor (MRT) is a highly aggressive disease, mainly affecting infants and small children. Material and methods: Between January 2007 and May 2021 a retrospective study was conducted at the Hospital de Pediatria J. P. Garrahan in Buenos Aires, Argentina, including 13 patients diagnosed with ERNC-MRT (extra-renal non-cerebral malignant rhabdoid tumor). Event-free survival (EFS) and overall survival (OS) were assessed using the Kaplan-Meier method and compared using the log-rank test. Results: Seven patients were less than 1 year old, all of them died. Four of 13 had metastatic disease, all of them in the lungs, 2 had locoregional lymph node involvement. Six achieved complete remission, 4 of them remained alive. Five received maintenance therapy (MT) with cyclophosphamide/vinorelbine, 4 were alive at last follow-up. Only one was studied for germline mutations, the result was negative. With a median follow-up of 126 months (range: 72-161), 3 and 5-year EFS and OS were 30.7% and 38.4%, respectively. Discussion: Although the sample size is small, survival rates are similar or slightly lower than other series. Age was the main prognostic factor. All but one patient that received MT are alive, suggesting that MT might have a role in ERNC-MRT; however, the prognostic significance is not entirely clear since there are multiple confounding factors.