The impact of distance in treating glioblastoma: a retrospective single-center study

Glioblastoma (GBM) is an aggressive primary brain tumor with poor overall survival. Patients living in rural areas have worse outcomes than those in metropolitan regions, but the effect of distance from subspecialty care on survival and clinical trial participation remains unclear. We evaluated the association between distance to a National Cancer Institute-designated Comprehensive Cancer Center (CCC) and overall survival (OS) and clinical trial enrollment in patients with isocitrate dehydrogenase wild-type GBM.

We retrospectively identified patients with newly diagnosed isocitrate dehydrogenase wild-type GBM (2021 World Health Organization classification) who received treatment at our CCC (2018-2022). Distance from the CCC was analyzed as both categorical and continuous variables. Univariable and multivariable Cox regression models were performed, adjusting for established prognostic factors.

The 167 patients had similar baseline characteristics across distance groups. In univariable analyses, no significant difference in OS was observed between patients living near the CCC and those at intermediate or far distances. In multivariable analysis, patients in the intermediate-distance group demonstrated significantly worse OS compared with the near group (hazard ratio 1.61, 95% confidence interval 1.03, 2.50, p = 0.035). Increasing distance was associated with significantly lower clinical trial enrollment (near 43%, intermediate 35%, and far 18%; p = 0.0001).

Distance from a CCC was associated with disparities in survival and access to clinical trials among patients with isocitrate dehydrogenase wild-type GBM. Given that clinical trials represent a standard-of-care option for GBM, strategies to improve access to subspecialty care and trial participation are needed to reduce outcome disparities.