Role of radiotherapy in supratentorial primitive neuroectodermal tumor in young children: results of the German HIT-SKK87 and HIT-SKK92 trials.

PURPOSE: To assess the outcome of young children with supratentorial primitive neuroectodermal tumor (stPNET) treated by intensive postoperative chemotherapy alone compared with treatment with chemotherapy and delayed radiotherapy (RT). PATIENTS AND METHODS: From 1987 to 1992, children younger than 3 years of age with stPNET were enrolled in the HIT-SKK87 trial in Germany and Austria. After surgery, low-risk patients received maintenance chemotherapy before RT. In high-risk patients, intensive induction chemotherapy was followed by maintenance chemotherapy until delayed RT was initiated. In the following trial, HIT-SKK92 methotrexate-based chemotherapy was applied. In children with complete remission after three cycles, therapy was finished without irradiation. Otherwise, radiotherapy or salvage chemotherapy was administered.
RESULTS: Twenty-nine children were eligible (age, 3.0 to 37.0 months). All children received chemotherapy. In 15 children, no RT was administered. Four children had tumor progression during chemotherapy and underwent irradiation. In 10 patients, RT was given after chemotherapy. Overall survival (OS) and progression-free survival (PFS) rates after 3 years were 17.2% and 14.9%, respectively. Twenty-four children relapsed (13 at the tumor site only, three at distant site, and eight at both local and distant sites). Positive impact on survival was observed in children with complete resection but without statistical significance. Administration of RT was the only significant predictive factor for OS and PFS. Only one child not having RT survived.
CONCLUSION: Outcome of infants and babies with stPNET is unsatisfactory. Omission of RT jeopardizes survival, even if intensive chemotherapy is applied. We suggest to limit any delay of RT to a maximum of 6 months even in young children.