Purpose: To evaluate local control, event-free survival, and overall survival for patients with parameningeal (PM) rhabdomyosarcoma (RMS) treated with intensive chemotherapy and delayed irradiation.
Patients and methods: Thirteen consecutive patients with PM RMS were treated with an institutional protocol from 1992 to 1998 at the University of Washington/Children's Hospital and Regional Medical Center and Deaconess Medical Center. Patients received intensive chemotherapy consisting of vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide prior to radiotherapy. Irradiation was delayed, in contrast to current Intergroup Rhabdomyosarcoma Study Group (IRSG) recommendations.
Results: Median follow-up was 39 months. Eleven patients had high-risk features, including five with intracranial extension. All patients responded to the intensive chemotherapy, with 38% exhibiting a complete response and the remaining 62% a partial response. Radiation was administered a median of 21 weeks from initiation of chemotherapy. The Kaplan-Meier estimate of 5-year local control was 92%, with event-free survival and overall survival rates of 83%.
Conclusions: With intensive induction chemotherapy, delayed irradiation for PM RMS does not compromise local control. Event-free survival and overall survival rates compare favorably with recently IRSG trials employing early irradiation. Delaying irradiation allows for intensification of chemotherapy and could permit response-based radiation volume and/or dose modifications, which could decrease treatment-related morbidity.