Favorable outcomes after whole abdominopelvic radiation therapy for pediatric and young adult sarcoma.

Abstract

Current Children's Oncology Group (COG) guidelines recommend 24 Gy whole abdominopelvic radiation therapy (WAP-RT) for pediatric patients with sarcoma with peritoneal dissemination and/or malignant ascites. However, WAP-RT has never been described for pediatric sarcoma excluding desmoplastic small round-cell tumor (DSRCT). The objective of this study was to evaluate feasibility, outcomes, and toxicity of WAP-RT in children with sarcoma and peritoneal dissemination. Detailed records of all 10 pediatric patients with sarcoma (excluding DSRCT) treated with WAP-RT from 2001 to 2013 were reviewed. Median age was 9.9 years (range, 1.7-33.8). Seven patients had rhabdomyosarcoma, 2 embryonal undifferentiated sarcoma of the liver, and 1 Ewing sarcoma. Patients received a median dose of 24 Gy with intensity-modulated radiation therapy (IMRT) to the whole abdomen and pelvis. Two patients did not complete treatment, one due to transfusion-resistant pancytopenia and one due to moderate acute gastrointestinal toxicity. At a median follow-up of 4.0 years, both relapse-free survival and overall survival were 100%. Acute hematologic toxicities were common, with 40% of patients developing a grade 4 hematologic toxicity. Most acute gastrointestinal toxicities were grade 1 and managed appropriately with anti-diarrheals and anti-emetics. Late effects varied, and half of patients are without long-term sequelae. All patients remain free of disease, both locally and distantly. Although WAP-RT was associated with acute and late toxicity, treatment was feasible with supportive care. Given the excellent rates of tumor control, we recommend that all providers give WAP-RT with IMRT to patients with pediatric sarcoma and peritoneal dissemination and/or malignant ascites.