High-dose chemotherapy and autologous stem cell rescue in children with newly diagnosed high-risk or relapsed medulloblastoma or supratentorial primitive neuroectodermal tumor.

BACKGROUND: Single or tandem double high-dose chemotherapy (HDCT) was used to treat children with newly diagnosed high-risk or relapsed medulloblastoma and supratentorial primitive neuroectodermal tumor (MB/sPNET) in order to defer or avoid radiotherapy in young children. PROCEDURE: Thirty-seven HDCTs were given to 25 children with newly diagnosed high-risk or relapsed MB/sPNET. Tandem double HDCT was used for 12 of 15 patients initially intended to receive double HDCT.
RESULTS: Three-year EFS (+/-SE) in 6 newly diagnosed high-risk (>3 years old), 8 newly diagnosed (<3 years old), and 11 relapsed MB/sPNET was 83.3 +/- 15.2%, 62.5 +/- 20.5%, and 29.1 +/- 15.7%, respectively. Three-year EFS for patients in CR or PR and in less than PR at first HDCT was 67.4 +/- 11.0% and 16.7 +/- 15.2%, respectively (P = 0.001). Three-year EFS in patients initially intended to receive double HDCT and single HDCT was 66.0 +/- 12.4% and 40.0 +/- 15.5%, respectively. For 19 patients in CR or PR at first HDCT, 3-year EFS was 88.9 +/- 10.5% in tandem double HDCT group, and 44.4 +/- 16.6% in single HDCT group, respectively (P = 0.037). Although four treatment-related mortalities (TRMs) occurred during 25 first HDCTs, no TRM occurred during 12 second HDCTs. In four of eight young children, craniospinal radiotherapy was successfully withheld without subsequent relapse.
CONCLUSIONS: High-dose chemotherapy may improve the survival of children with newly diagnosed high-risk MB/sPNET, and, to some extent, the survival of those with relapsed MB/sPNET. Further study is necessary to elucidate the efficacy of tandem double HDCT.