Age-specific disparities in rural and urban survival among patients with IDH-wildtype glioblastoma: a...

Access to subspecialty neuro-oncologic care is uneven across the United States. Whether rural residence is linked to age-specific survival differences in IDH-wildtype glioblastoma (GBM) is unclear.

We used the Surveillance, Epidemiology, and End Results (SEER) 17 database to identify adults (≥ 18 years) with histologically confirmed IDH-wildtype GBM (diagnoses 2018-2022). Rural-urban residence followed 2013 USDA Rural-Urban Continuum Codes (1-3 urban; 4-9 rural). Overall survival (OS) was the primary endpoint. After confirming violation of proportional hazards, we fit multivariable accelerated failure time (AFT) models and report time ratios (TRs) adjusted for area of residence, age group (18-64 vs ≥ 65 years), sex, race, surgery, radiotherapy, and chemotherapy; age-specific effects were assessed by stratification.

Among 10,632 patients, 1,193 (11.2%) resided in rural and 9,439 (88.8%) in urban counties. Rural patients were slightly older and were less likely to receive radiotherapy (71.8 vs 76.7%) or chemotherapy (69.2 vs 73.4%); resection rates were similar (84.4 vs 83.8%). One- and two-year OS was 37 and 14% in rural areas versus 45% and 19% in urban areas. In adjusted AFT models, rural residence was associated with shorter survival (TR 0.89 95% CI 0.84-0.95). The association was more evident in adults aged 18-64 years (TR 0.86, 95% CI 0.79-0.94), whereas the estimate in those aged ≥ 65 years was smaller and not statistically significant (TR 0.95, 95% CI 0.87-1.03). Not receiving surgery (TR 0.59), radiotherapy (TR 0.51), or chemotherapy (TR 0.42) was strongly associated with shorter survival.

Rural residence was associated with shorter OS in IDH-wildtype GBM. The association was more evident in adults aged 18-64 years.