Clinical Outcomes and Efficacy of Stereotactic Body Radiation Therapy in
Children, Adolescents, and Young Adults with Metastatic Solid Tumors
Abstract
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.