Short Hypofractionated Radiation Therapy in Palliation of Pediatric Malignancies: Outcomes and Toxicities

Purpose: Treatment strategies in palliation of pediatric cancer remain a significant challenge. In this study, we aimed to assess the efficacy and safety of a short course of hypofractionated radiation therapy (RT) for metastatic or recurrent childhood tumors. Methods and Materials: A total of 104 lesions in 62 pediatric patients with metastatic or recurrent cancer were treated with a short hypofractionation schedule (>1 but ≤5 fractions; ≥3 Gy per fraction) between 2007 and 2017 in our institution. The primary endpoint was local control (LC). Other endpoints included treatment response, overall survival, progression-free survival, and toxicity. Toxicities were assessed using the Common Terminology Criteria for Adverse Events v.4.0. Results: The most common histologies were neuroblastoma, comprising 50 of the 104 lesions (48.1%); osteosarcoma, 17 lesions (16.4%); and Ewing sarcoma, 13 lesions (12.5%). A median total dose of 24 Gy was delivered in a median of 5 fractions. Of 104 lesions, 26 (25.0%) were treated with stereotactic body radiation therapy, 24 (23.1%) with intensity modulated RT, and 48 (46.2%) with 2-dimensional RT or 3-dimensional conformal RT. A complete or partial response was observed in 63 (60.6%) of lesions, and stable disease was observed in 34 (32.7%). At a median follow-up of 8.7 months, 21 local failures occurred (20.2%). The 1- and 2-year LC rates were 74% and 68%, respectively. LC was better for tumors without previous irradiation (83% vs 57% with previous RT; P =.004). LC rates did not differ between RT techniques or total biologically effective dose with α/β ratio of 10 (BED10) (≤30 vs >30 Gy). At the time of analysis, 38 deaths in the cohort of 62 patients (61.3%) were recorded. The 1-year progression-free survival and overall survival rates were 31% and 44%, respectively. Incidence of any grade ≥3 toxicity was 6.7% (7 of 104). No grade 5 events occurred. Conclusions: A short hypofractionation scheme yields effective disease control and treatment response with a favorable side effect profile. Select pediatric patients with symptomatic metastases or recurrent disease can be considered for a short course of palliative RT.