The landscape of mortality during or within 30 days after non-palliative radiotherapy across 11 major cancer types.

6570 Background: The rate of peri-RT mortality (death that occurs during or within 30 days after non-palliative radiotherapy) has not been previously characterized. Risk factors and predictors for peri-RT mortality are unknown. Methods: Adult and pediatric patients with non-metastatic cancer who received non-palliative external beam radiation between 2004-2016 were identified in the National Cancer Database for 11 cancer types: breast, prostate, genitourinary (non-prostate), bone/soft tissue, gynecological, head/neck, lymphoma, gastrointestinal, small cell lung, non-small cell lung, and central nervous system (CNS). Multivariable logistic regression was used to identify predictors of peri-RT mortality while controlling for 16 covariates, including patient, tumor, and treatment factors. Results: Approximately 1.32 million patients were identified. Peri-RT mortality was 2.8% overall but spanned 2 orders of magnitude depending on cancer type, ranging from 0.1% for breast cancer to 8.6% for CNS malignancies. Other cancers with > 5% peri-RT mortality were non-prostate genitourinary, small cell lung, and non-small cell lung. Peri-RT mortality steadily improved from 3.5% in 2004 to 2.0% in 2016 ( P <.0001). Major predictors of peri-RT mortality were cancer stage, older age, baseline comorbidity, and lack of private insurance, while male sex, Black race, and geographical region were associated with modestly increased risk (all P <.0001). Conversely, treatment at an academic center, higher patient volume at the treating facility, concurrent chemotherapy, and intensity-modulated radiotherapy were associated with modestly decreased risk (all P <.0001). Among patients receiving stereotactic radiotherapy, peri-RT mortality was 1.0% (adjusted odds ratio 0.27, 95% confidence interval 0.24-0.30, P <.0001), underscoring the excellent safety record of this treatment approach. Conclusions: Peri-RT mortality varied considerably as a function of multiple disease-specific and sociodemographic differences, which highlight potential areas of health disparities. Early recognition of patients at increased risk may facilitate closer monitoring or other prophylactic interventions.