Primitive cerebral neuroectodermal tumors excluding medulloblastomas: A retrospective study of 30 cases

We present a retrospective study of 30 cases of primitive cerebral neuroect odermal tumors (PNET), excluding medulloblastomas, referred to us postopera tively for additional therapy to evaluate prognostic factors and treatment efficiency. The histologic types were: pinealoblastomas (n = 7); ependymobl astomas (n = 2); medulloepitheliomas (n = 4), and other PNET (n = 17). The tumor was located in the supratentorial area in 24 patients and in the post erior fossa in 6 patients. Among the supratentorial tumors, 8 were metastat ic, Maximal surgical resection was performed, Sixteen of 30 patients had no measurable disease after surgery and were considered as standard-risk (SR) cases, and 14 with a local residue or metastasis as high-risk (HR) cases. The objective of postsurgical treatment was to avoid radiotherapy in childr en below 4 years of age. It consisted of radiotherapy alone in 6 patients, chemotherapy alone in 17, and radiotherapy with chemotherapy in 7. Furtherm ore, high-dose chemotherapy (busulfan, thiotepa) and autologous bone marrow transplantation, performed in 6 patients, yielded a response rate of 3/6, Event-free survival (EFS) of SR patients was 37% at 3 years (95% confidence interval (CI) 14-60%) and overall survival 44% (95% CT 26-62%), Only 1 of the HR patients achieved a complete remission and all of them died early. T he critical prognostic factors appear to be the completeness of initial sur gical resection and absence of metastasis, These tumors have a poor prognos is. Novel strategies (high-dose chemotherapy) are needed to improve their o utcome because the children concerned are very young and the effects of rad iotherapy are particularly deleterious when tumors are situated in the supr atentorial area.