High-dose chemotherapy with autologous hematopoietic stem cell transplantation in children with atypical teratoid/rhabdoid CNS tumors
Atypical teratoid rhabdoid tumor (ATRT) of central nervous system (CNS) is an aggressive malignancy with poor prognosis, predominantly observed in young children. There are no established approaches to CNS ATRT management nowadays. This retrospective study aimed to analyze the effectiveness and prognostic factors of high dose chemotherapy with autologous hematopoietic stem cell transplantation HDCT/auto-HSCT in pediatric CNS ATRT. Thirty CNS ATRT patients treated with HDCT/auto-HSCT were enrolled in the analysis. Median age was 19.5 months. There were 11 (36.6%) infants and 19 (63.4%) children older than 12 months, among them 21 (70%) boys and 9 (30%) girls. Infratentorial tumor was diagnosed in 7 patients (56.7%) and supratentorial in 13 (43.3%). All children initially received surgery with total resection (n=8, 26.7%), subtotal resection (n=9, 30%), partial resection (n=11, 36.6%) and biopsy (n=2, 6.7%). The majority of patients had M+ stage (n=16, 53.3%) and the minority had M-0 stage (n=12, 40%), while stage wasn't clarified (Mx) in 2 (6.7%) cases. After surgery everyone received treatment according to various protocols: EU-RHAB (n=12, 40%), MUV-ATRT (n=11, 36.7%), individual therapy (n=7, 23.3%). Radiotherapy (RT) was performed in 24 children (80%) after HDCT/auto-HSCT. The majority of patients (n=22, 73.3%) received intraventricular/intrathecal chemotherapy. The disease status was assessed in all cases prior to HDCT/auto-HSCT with complete response (CR) in 12 (40%), partial response (PR) in 8 (26.7%) and stabilization (S) in 10 (33.3%). Single auto-HSCT was performed in the majority of patients (n=21, 70%) and tandem transplants were carried out in 9 cases only (30%). In total, 39 transplants were performed. Peripheral blood hematopoietic stem cells (PBSC) were the transplant source in 27 children (90%), and combination of PBSC and bone marrow (BM), in 3 (10%). Five-year event-free survival (EFS) and overall survival (OS) were 44%. The majority of relapses were diagnosed during first 24 months after disease onset. These data are comparable to the most international results. Survival of CNS ATRT patients after HDCT/auto-HSCT was statistically significantly higher after total tumor resection, RT, intraventricular/intrathecal chemotherapy, and CR prior to transplantation.