Prognostic factors in children with supratentorial (nonpineal) primitive neuroectodermal tumors. A neurosurgical perspective from the Children's Cancer Group.
Supratentorial primitive neuroectodermal tumors (S-PNETs), which have also been called cerebral neuroblastomas, have been considered to be the hemispheric equivalent of posterior fossa medulloblastomas. Twenty-seven children with S-PNETs (excluding pineoblastomas) which were confirmed by central pathology review were treated on the CCG-921 protocol from 1986 to 1992. After operation, all patients were staged with CSF cytology and spinal myelography or magnetic resonance scans and were treated with craniospinal irradiation and chemotherapy. Data from these 27 patients have been reviewed to evaluate neurosurgical treatment, survival, and prognostic variables that correlate with survival. Overall survival at 5 years was 34% (SE 20%) and progression-free survival (PFS) was 31% (SE 18%), which is lower than the survival of patients with posterior fossa PNETs (medulloblastomas). PFS was significantly worse in children 1.5-3 years of age at diagnosis and in those with evidence of tumor dissemination at the time of diagnosis. Large preoperative tumors were more likely to be associated with greater than 1.5 cm2 residual tumor postoperatively. Neurosurgeons estimated that less than 1.5 cm2 of residual tumor was present in 52% of the cases; postoperative scans confirmed that in 58%. For children with less than 1.5 cm2 residual tumor, postoperative survival at 4.0 years was 40% (SE 22%); for those with greater than 1.5 cm2 residual tumor, survival was 13% (SE 8%). The difference did not reach statistical significance, due to small numbers in this series, though a trend did exist (p = 0.19). Large series will be required to clarify the effects of extent of resection on survival.