Pelvic neuroblastoma--implications for a new favorable subgroup: a Children's Cancer Group experience.

BACKGROUND: The survival in neuroblastoma is influenced by patient age, disease stage, tumor site, and several biologic factors. This study was undertaken to determine if primary pelvic lesions are associated with an unusually favorable outcome. METHODS: Nine hundred eighty-six patients registered on Children's Cancer Group studies from 1980 to 1993 were reviewed, and 41 (4.3%) were found to have pelvic tumors. Survival was analyzed, and correlations among age, stage of disease, surgical resectability, histopathology, serum ferritin, and N-myc oncogene amplification were evaluated. RESULTS: Age at diagnosis was comparable between patients with pelvic and nonpelvic tumors. Disease distribution was similar, with stages III and IV comprising 78% (32 of 41) of pelvic lesions compared with 73% (692 of 945) for nonpelvic tumors. There was no outcome difference in favorable stages (I, II, and IV-S), with 3-year progression-free survival rates of 88% and 82% for pelvic and nonpelvic sites, respectively. However, in stages III and IV, the 3-year progression-free survival was 70% for pelvic lesions compared with 47% for nonpelvic tumors (p = 0.04). Some favorable biologic factors were more common in children with pelvic lesions. CONCLUSIONS: The pelvis is an unusual primary site for neuroblastoma but represents a more favorable prognostic subgroup, which is most evident in advanced-stage disease.