Results of intensive therapy in children with localized alveolar extremity rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study.

Abstract

Preliminary analyses of treatment results and prognostic factors from the first Intergroup Rhabdomyosarcoma Study (IRS I) suggested that alveolar histology and extremity site were among factors associated with an adverse outcome in clinical group I patients whose tumors had been completely resected. A high incidence of alveolar histology among the extremity tumors compounded the problem. These findings prompted an amendment to IRS II shortly after the study opened. Therapy for patients with alveolar extremity tumors in groups I and II was changed to more intensive repetitive pulse vincristine, dactinomycin, and cyclophosphamide (VAC) for 2 years. The outcome of 44 patients who received intensive therapy on IRS II is compared with a control series of 30 patients who were treated on IRS I. The control patients received standard VAC therapy for 2 years or VA for 1 year. Half of group I control patients received local radiotherapy, whereas none was given to group I intensive therapy patients. In both studies group II patients received radiotherapy to the primary tumor site and to identified positive regional lymph nodes. Compared with the control group, patients given more intensive therapy had a longer disease-free survival (DFS) (69% v 43% at 3 years), but this was of marginal significance (P = .06). The overall survival difference (77% v 57% at 3 years) was not significant (P = .23). Despite the limited statistical evidence, there is some indication that intensive therapy improved the prognosis of children with localized alveolar rhabdomyosarcoma (RMS).