Curative-intent radiotherapy for pediatric osteosarcoma: The St. Jude experience

Area of Science:

• Oncology
• Radiation Oncology
• Pediatric Oncology

Background:

• Limited studies exist on radiation therapy (RT) efficacy in pediatric and adolescent and young adult (AYA) osteosarcoma patients.
• RT is known to improve local tumor control and survival in some osteosarcoma cases.

Purpose of the Study:

• To evaluate the efficacy and toxicity of curative-intent RT in pediatric and AYA osteosarcoma patients.
• To identify prognostic factors for local failure and overall survival in this population.

Main Methods:

• Retrospective review of 28 pediatric and AYA osteosarcoma patients treated with curative-intent RT (1990-2017).
• Analysis of local failure (LF) using cumulative incidence and overall survival (OS) using Kaplan-Meier methods.
• Competing-risk regression and Cox proportional hazards models were used to determine outcome predictors. Toxicity was assessed using CTCAE v4.0.

Main Results:

• With a median follow-up of 99.1 months, 32.1% of patients experienced local failure.
• Estimated 5-year cumulative incidence of LF was 32.7% for the cohort, 25.0% for primary disease, and 43.8% for recurrent/refractory disease.
• Estimated 5-year OS was 42.6% for the cohort, 54.6% for primary disease, and 24.3% for recurrent/refractory disease. Lack of chemotherapy or metastasis at RT predicted decreased OS.
• 11 patients experienced RT-related morbidity, including two grade 3 toxicities.

Conclusions:

• Curative-intent RT is well-tolerated in pediatric and AYA osteosarcoma patients.
• RT achieved a 75% local tumor control rate in patients with primary disease, comparable to adult studies.
• Prognostic factors for survival in this population warrant further investigation.