Sujith Baliga

and 15 more

Purpose Pediatric patients with metastatic solid tumors historically have a poor overall survival. Some pediatric patients may still be potentially curable with aggressive local therapy to metastatic disease. The purpose of this study is to report results of the use of SBRT in the treatment of pediatric metastatic disease. Materials and Methods Pediatric patients who received SBRT between the years 2000-2020. Study endpoints included local control (LC), progression free survival (PFS), overall survival (OS), cumulative incidence (CI) of death or local failure and toxicity. The endpoints with respect to survival and LC were calculated using the Kaplan-Meier estimate. The cumulative incidence of local failure was calculated using death as a competing risk. Results 16 patients with 36 lesions irradiated met inclusion criteria. The median OS and PFS was 17 months and 15.7 months, respectively. The 1-year OS was 75%. The 6- and 12-month LC was 85% and 78%, respectively. There were no local failures in lesions receving a BED10≥100 Gy. Patients who had ≤5 metastatic lesions at first recurrence had a superior 1-year OS of 100% versus 50% with >5 lesions. One patient (6.3%) experienced a grade 3 CNS toxicity. Conclusions LC was excellent with SBRT delivered to metastatic disease, particularly for lesions receiving a BED10≥100 Gy. High-grade toxicity was rare in our patient population. Patients with ≤5 metastatic sites have a significantly better OS compared to >5 sites. Future prospective trials with multi-institutional collaboration will be necessary to evaluate appropriate patient selection and the optimal radiation dose regimen.