Impact of Consolidative Radiation on Overall and Progression Free Survival in Pediatric, Adolescent and Young Adult Metastatic Bone and Soft Tissue Sarcoma
Menée à l'aide de données portant sur 85 patients atteints d'un sarcome métastatique des os ou des tissus mous avant l'âge de 40 ans (âge médian au diagnostic : 14,8 ans ; durée médiane de suivi : 25 mois), cette étude évalue l'efficacité, du point de vue de la survie globale et de la survie sans progression, d'une radiothérapie de consolidation
Purpose: To determine the association between consolidative radiation (RT) and survival in children, adolescents and young adults (AYA) with metastatic sarcoma Methods: Eligibility criteria included patients aged ≤39 years with newly diagnosed metastatic bone or soft tissue sarcoma who completed local control of the primary tumor without disease progression. Consolidative RT was defined as RT to all known sites of metastatic disease. Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). The least absolute shrinkage and selection operator (LASSO) Cox provided adjusted estimates. To account for immortal time bias, consolidative RT was used as a time varying covariate in a time dependent Cox model. Distant failure was estimated using the Fine-Gray model. Results: Patients (n=85) had a median age at diagnosis of 14.8 years. Most common histology was Ewing Sarcoma (EWS) (45.9%) followed by rhabdomyosarcoma (40.0%). Receipt of consolidative RT was associated with EWS (p<0.001) and local control modality as those who underwent local control with surgery and RT compared to surgery alone were more likely to be treated with consolidative RT (p=0.034). Consolidative RT was independently associated with improved OS (Hazard ratio (HR): 0.41, 95% CI: 0.17, 0.98, p=0.045) and improved PFS (HR: 0.37, 95% CI: 0.16, 0.88, p=0.024) after adjusting for confounding variables and immortal time bias. Patients treated with consolidative RT also experienced a lower risk of distant failure (HR: 0.33, 95% CI: 0.17 – 0.64, p=0.001). In an independent dataset of patients with metachronous progression (n=36), consolidative RT remained independently associated with improved OS. Conclusion: Consolidative RT was independently associated with improved OS and PFS and decreased risk of distant failure in children and AYA patients with metastatic sarcoma. Future work should evaluate biomarkers to optimize patient selection, timing and dose for consolidative RT.
International Journal of Radiation Oncology, Biology, Physics