PRIMITIVE NEUROECTODERMAL TUMORS - ANATOMIC LOCATION, EXTENT OF SURGERY, AND OUTCOME

Background/Purpose: Primitive neuroectodermal tumours (PNET) are rare tumours sharing similar histology, immunohistochemistry, and cytogenet ics to Ewing's sarcomas. The aim of the study was to document the effe ct of site of origin and the completeness of surgical excision on the outcome in infants and children with PNET. Methods: All patients (n = 26) with PNET treated in our hospital during the last 6 years were inc luded in the study. The diagnosis was based on the histopathologic fin dings and a positive MIC2 antibody test. The tumours were classified a ccording to the Intergroup Rhabdomyosarcoma Study III, and were treate d according to the UKEESG protocol for Ewing's Sarcoma. Results: Compl ete remission (CR) was achieved in 52% of the patients completing thei r chemotherapy. Overall, survival was 42% (11 of 26). Tumours from the paraspinal and scapula areas responded relatively well (CR, 83%), whe reas abdominal PNET did not respond to treatment. Tumours arising from the head, neck, or chest had an intermediate prognosis (37% survival) . Three of the 10 patients who had a complete excision of the tumour d ied of progressive disease. Conclusions: Complete surgical excision re duced the risk of local recurrence but did not prevent metastatic spre ad. These data indicate that PNET have a worse prognosis and different favourable sites than other sarcomas. New treatment strategies are ne cessary for these rare tumours. Copyright (C) 1998 by W.B. Saunders Co mpany.