Delayed radiation therapy timing and use of intensity-modulated radiation therapy in non-head and neck pediatric rhabdomyosarcoma

Abstract

Objective The impact of radiation therapy (RT) timing and use of intensity-modulated radiation therapy (IMRT) in nonhead and neck pediatric rhabdomyosarcoma (RMS) is underreported. Methods Children with non-head and neck RMS treated definitively with chemotherapy and RT from December 2000 through May 2010 at our institution were identified for analysis. Kaplan–Meier estimates of time to local progression-free survival (PFS), disease-free survival, and overall survival were performed, and Cox proportional hazard model examined the relationship between local control and RT timing and the use of IMRT. Results Thirty seven children, including 25 patients with non-metastatic disease, 12 patients with metastatic disease, and a total of 44 tumors were identified. Three-year local PFS was 87 % (95 % CI: 0.79–0.93) for the non-metastatic group and 76 % (95 % CI: 0.63–0.88) for the metastatic group. Among the non-metastatic group, the median time from the start of chemotherapy to RT was 17 weeks (range 4–43) with only four patients treated within ≤12 weeks. Median RT timing for the metastatic group was 21 weeks (range 15–68). Among all patients, IMRT was used in 17 (39 %) cases. No significant association between local control and RT timing or use of IMRT was found. Conclusion Our data demonstrate good rates of local tumor control with delayed RT timing of greater than 12 weeks and the use of IMRT in a subset of pediatric patients with nonhead and neck RMS.