3713 - Sociodemographic Factors Informing Overall Survival in Patients Treated with SBRT

Purpose/Objective(s): Stereotactic body radiotherapy (SBRT) is used for the treatment of oligometastatic and oligoprogressive disease in conjunction with increasingly effective systemic therapies. While clinical factors associated with improved outcomes following SBRT have been studied, the contribution of sociodemographic factors is less well characterized. The current study aims to evaluate associations between sociodemographic factors and overall survival (OS), as well as use of systemic therapies, in patients treated with SBRT for metastatic disease.

Materials/Methods: Patients who received SBRT to extracranial sites of metastatic cancer between 2014-22 at a single academic institution were identified, and medical records were reviewed to collect demographics, disease treatment details, and clinical outcomes. Insurance status was characterized as Medicare/Medicaid, private, or uninsured. A sub-cohort of patients with non-small cell lung cancer (NSCLC) and melanoma was evaluated separately. Chi-square analysis was performed to evaluate the association between receipt of systemic therapies and sociodemographic factors. Kaplan-Meier survival analysis with log-rank test was performed to compare survival distributions between groups.

Results: We identified 572 patients, with the most common primary cancers NSCLC (20%), breast (18%), renal cell (12%), colorectal (11%), and melanoma (9%). On Kaplan-Meier analysis, insurance and marital status were significantly associated with survival outcomes (Table 1) and not sex, race, or ethnicity. Among the sub-cohort of patients with NSCLC and melanoma, 91 received immunotherapy and 75 did not. Median survival for patients who received immunotherapy was 16.3 months (95% CI [0.0 - 36.4]) and 10.8 months (95% CI [6.7 - 14.9]) for those who did not (p = 0.017). Insurance status significantly correlated with receipt of immunotherapy, with 62% of privately insured, 44% of those with Medicare/Medicaid, and 30% of uninsured receiving immunotherapy (p = 0.039).

Conclusion: Sociodemographic factors including insurance and marital status can impact survival outcomes for patients treated with SBRT for metastatic cancer, which could reflect differences in access to care and/or ability to adhere to recommended treatment. These results highlight the importance of recognizing and addressing sociodemographic factors in caring for this group of patients.