3705 - Delay vs. Non-Receipt of Post-Craniotomy Radiation Therapy: Association of Facility Availability, Proximity, and Social Vulnerability
Presenter(s)
P. F. Orio III1, M. A. Garcia2, T. Frandsen2, and P. M. Devlin3; 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, 2GT Medical Technologies, Tempe, AZ, 3Department of Radiation Oncology, Brigham and Women’s Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
Purpose/Objective(s):
After malignant brain tumor resection, adjuvant radiation therapy (RT) is time sensitive, yet delays and non-receipt remain common and poorly characterized. We examined whether facility availability, proximity, and social vulnerability are differentially associated with delayed initiation versus non-receipt of postoperative RT.
Materials/Methods:
Adults who underwent a craniotomy for malignant brain tumors (primary and secondary) in 2023 were identified in an all-payer claims dataset (18,885 patients treated in 548 hospitals). Records were linked to measures of socioeconomic vulnerability (Social Vulnerability Index [SVI] and American Community Survey indicators) and structural access metrics. Patients who died/entered hospice within 90 days were excluded and required to have observable claims through 90 days. Exposures were proximity to the nearest RT-capable facility (closeness) and Hospital Referral Region (HRR)-level RT center density (centers per 100,000). RT included fractionated and SRS. Outcomes were RT initiation within 42 days and no observed RT claim within 90 days (non-receipt). Mixed-effects logistic regression evaluated independent associations and tested for interactions.
Results:
Among 18,885 patients, 51.1% had no observed RT claim within 90 days and only 29.2% initiated RT within 42 days (59.7% among those with any RT within 90 days). Being closer to the nearest RT facility was independently associated with timely initiation (aOR per IQR=1.12, 95% CI 1.08-1.17) but was not associated with reduced non-receipt. Higher RT center density was associated with improved timely initiation (aOR per IQR=1.18, 95% CI 1.11-1.25) and lower odds of non-receipt (aOR per IQR=0.84, 95% CI 0.78-0.90). Transportation vulnerability was associated with lower odds of timely initiation (aOR 0.82, 95% CI 0.78-0.88) and higher odds of non-receipt (aOR 1.12, 95% CI 1.07-1.17). Housing cost burden showed similar associations (timely initiation aOR 0.87, 95% CI 0.78-0.97; non-receipt aOR 1.14, 95% CI 1.02-1.28). Higher RT center density attenuated but did not eliminate the transportation effect (transportation-by-density interaction aOR=1.08, 95% CI 1.02-1.14; p=0.01).
Conclusion:
Market-level RT facility availability was strongly associated with non-receipt of postoperative RT, while proximity to the nearest RT facility primarily affected timeliness among treated patients. Socioeconomic barriers persisted even in high-availability regions. These findings suggest that expanding RT facility availability may reduce non-receipt, but persistent social vulnerability argues for targeted strategies when RT delivery is unlikely, even in high-supply markets. Distinguishing delay from non-receipt provides a framework for identifying patients at high risk of failure to initiate postoperative RT.