A Phase II Study of Preradiotherapy Chemotherapy Followed by Hyperfractionated Radiotherapy for Newly Diagnosed High-Risk Medulloblastoma/Primitive Neuroectodermal Tumor: A Report From the Children's Oncology Group (CCG 9931)

Purpose

To verify feasibility and monitor progression-free survival and overall survival in children with high-risk medulloblastoma and noncerebellar primitive neuroectodermal tumors (PNETs) treated in a Phase II study with preradiotherapy chemotherapy (CHT) followed by high-dose, hyperfractionated craniospinal radiotherapy (CSRT).

Methods and Materials

Eligibility criteria included age >3 years at diagnosis, medulloblastoma with either high M stage and/or >1.5 cm² postoperative residual disease, and all patients with noncerebellar PNET. Treatment was initiated with five alternating monthly cycles of CHT (A [cisplatin, cyclophosphamide, etoposide, and vincristine], B [carboplatin and etoposide], A, B, and A) followed by hyperfractionated CSRT (40 Gy) with a boost to the primary tumor (72 Gy) given in twice-daily 1-Gy fractions.

Results

The valid study group consisted of 124 patients whose median age at diagnosis was 7.8 years. Eighty-four patients (68%) completed the entire protocol according to study guidelines (within 9 months), and the median time to complete CSRT was 1.6 months. Major reasons for failure to complete CHT included progressive disease (17%) and toxic death (2.4%). The 5-year progression-free survival and overall survival rates were 43% ± 5% and 52% ± 5%, respectively. No significant differences were detected in subset analysis related to response to CHT, site of primary tumor, postoperative residual disease, or M stage.

Conclusions

The feasibility of this intensive multimodality protocol was confirmed, and response to pre-RT CHT did not impact on survival. Survival data from this protocol can not be compared with data from other studies, given the protocol design.

PNET, Medulloblastoma (high risk), Hyperfractionated radiotherapy, Preradiation chemotherapy