Influence of different treatment modalities on the curability of childhood rhabdomyosarcoma of the head or neck

We reviewed the clinical courses of 43 patients with localized and regional rhabdomyosarcoma primary in the head or neck treated according to three sequential plans of combined-modality therapy to identify independent contributions of surgery, chemotherapy and radiotherapy to disease control, survival and development of central nervous system (CNS) involvement. In the majority of patients complete surgical resection was not feasible by vitrue of tumor location or extent of disease. Combinations of vincristine, cyclophosphamide, and dactinomycin with or without adriamycin were used simultaneously or sequentially with irradiation to induce tumor regression. Radiation doses ranged from 35 to 55 Gy. In the sequential treatment group, six of 22 patients with measurable disease had complete responses to chemotherapy. Ten of 11 partial responders and 2 of 5 non-responders to chemotherapy attained complete responses with addition of radiotherapy (82% overall CR). Simultaneous chemotherapy and irradiation induced complete responses in 4 of 9 patients. Local control of minimal residual disease was uniformly achieved with radiation dose of < 50 Gy, but similar doses were effective in only 11 of 26 patients with gross residual disease. Twenty-three percent of patients developed CNS involvement as a consequence of uncontrolled or recurrent primary tumors. Although local tumor control was achieved in 79% of patients, it could not be maintained in more than 63%. Twenty-four patients (56%) have been surviving disease-free for 2.5 to 15.5 years (median 7.5 years). We conclude that a 6-week course of chemotherapy preceding radiotherapy does not result in loss of short term disease control of unresectable primary tumor. Radiation doses < 50 Gy appear adequate for eradication of minimal residual disease but inadequate for gross disease.