Outcome and prognostic factors for children with supratentorial primitive neuroectodermal tumors treated with carboplatin during radiotherapy: a report from the Children's Oncology Group.

Background: Supratentorial PNETs (sPNET) are uncommon embryonal malignancies of the central nervous system whose prognosis has historically been poor. We evaluated the outcome and prognostic factors of children with sPNET treated prospectively on a Children's Oncology Group trial.

Procedure: Following surgery, patients received craniospinal radiotherapy with concurrent carboplatin followed by six months of maintenance chemotherapy with cyclophosphamide and vincristine.

Results: Five-year overall survival (OS) and progression-free survival (PFS) for all patients was 58 ± 7% and 48 ± 7%. For patients with pineoblastoma (n = 23), five-year OS and PFS was 81 ± 9% and 62 ± 11%. Extent of resection but not M-stage was prognostic. Five-year OS and PFS for 37 patients with non-pineal tumors (NPsPNET) was 44 ± 8% and 39 ± 8%, significantly worse than for PB (P = 0.055 and 0.009 respectively). Extent of resection and major radiotherapy deviations were prognostic. Five year OS was 59 +/- 11.4% for those undergoing complete resection versus 10.4 +/- 7% for those who did not (P = 0.017). Central pathologic review called 14 (38%) "classic" sPNET, 8 (22%) "undifferentiated" and 13 (35%) "malignant gliomas." There was no significant difference between the subgroups, although survival distributions approached significance when the combined "classic" and "undifferentiated" group was compared to the "malignant gliomas."

Conclusions: Carboplatin during RT followed by 6 months of non-intensive chemotherapy is a feasible treatment strategy for patients with sPNET. Aggressive surgical resection should be attempted if feasible. The classification of supratentorial small cell malignancies can be difficult.