Metastatic-Site Radiation Therapy for Ewing Sarcoma and Rhabdomyosarcoma: Consensus Guidelines From the National Pediatric Cancer Foundation.

PURPOSE: Despite the urgent need for improved outcomes in patients with metastatic Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS), it is unknown how to best approach metastatic-site radiation therapy for these patients and whether such treatment provides a significant oncologic benefit that outweighs the toxicities. METHODS AND MATERIALS: We gathered a panel of pediatric radiation oncologists from academic hospitals to identify and discuss current controversies regarding the role of radiation in the management of metastatic EWS and RMS. The panel reviewed existing clinical data and ongoing trials to address 5 key questions: (1) the role of whole lung irradiation (WLI) in treating lung metastases; (2) the number of metastatic sites warranting radiation therapy and the radicality of such an approach; (3) radiation techniques, including stereotactic body radiation therapy (SBRT); (4) the timing of metastatic-site radiation therapy; and (5) the utility of metastatic-site radiation therapy for relapsed metastatic disease. RESULTS: After a review of existing data, consensus recommendations were developed to support the decision-making process in metastatic-site irradiation, aiming to improve long-term disease control. Patients with pulmonary metastases should receive WLI. In patients with limited (<8 sites) metastatic disease, a comprehensive approach should be taken to treat all sites of metastatic disease diagnosed at presentation. SBRT should be considered as a preferred treatment technique. The timing of metastatic-site treatment should coincide with the end of systemic therapy. However, if there is a dosimetric advantage or improved compliance, concurrent treatment with the primary site may be preferred. CONCLUSIONS: A consensus guideline was established to address several critical questions regarding the role of radiation in the treatment of metastatic EWS and RMS. The study highlights the existing controversies, provides a structured approach, and underscores the need for future studies to further evaluate the therapeutic ratio of metastatic-site directed therapy.

Duke Scholars

Author Nicole A. Larrier Radiation Oncology