Special considerations related to primary site in rhabdomyosarcoma: experience of the Intergroup Rhabdomyosarcoma Study, 1972--76.

Rhabdomyosarcomas (RMS) arising in the head and neck region, retroperitoneum, and perineum were considered together here because the usual surgical approach is incisional biopsy. Thus successful treatment of these neoplasms depends on effective radiation therapy and chemotherapy. From November 1972 through December 1976 the Intergroup Rhabdomyosarcoma Study accrued 127 patients with primary tumors in the head and neck, 34 with orbital tumors, 24 with sarcomas arising in the retroperitoneum-pelvis (no genitourinary), and 11 with perineal lesions. Results of treatment varied among these primary sites. Patients with orbital RMS had the best prognoses; 77% of them were free of disease, compared with a 51% disease-free rate in patients with nonorbital head and neck RMS. In this latter group, disease recurrence was evenly divided among local failure, distant metastases, and direct meningeal extension. Prognoses were similar for retroperitoneal tumors; 46% of such patients are currently free of disease. That the perineum was a rare site for RMS was fortunate because only 3 of 11 such patients (27%) are free of detectable disease now (January 1979). We concluded that the site of the primary tumor is an important prognostic variable in children with RMS.