Association between urbanicity and surgical treatment among patients with primary glioblastoma in the United States

Background. Glioblastoma (GB) is the most common and most lethal primary malignant brain tumor. Extent of surgical resection is one of the most important prognostic factors associated with improved survival. Historically, patients living in nonmetropolitan counties in the United States have limited access to optimal treatment and health care services.The aim of this study is to determine whether there is an association between urbanicity and surgical treatment patterns among US patients with primary GB. Methods. Cases with histologically confirmed, primary GB diagnosed between 2005 and 2015 were obtained from the Central Brain Tumor Registry of the United States (CBTRUS) in collaboration with the Centers for Disease Control and Prevention, and the National Cancer Institute. Multivariable logistic regression models were constructed to assess the association between urbanicity and receipt of surgical treatment (gross total resection [GTR]/subtotal resection [STR] vs biopsy only/none) and extent of resection (GTR vs STR), adjusted for age at diagnosis, sex, race, US regional division, and primary tumor site. Results. Patients residing in nonmetropolitan counties were 7% less likely to receive surgical treatment (odds ratio [OR] = 0.93, 95% CI: 0.89-0.96, P < .0001). Among those who received surgical treatment, metropolitan status was not significantly associated with receiving GTR vs STR (OR = 0.99, 95% CI: 0.94-1.04, P = .620). Conclusions. Among US patients with GB, urbanicity is associated with receipt of surgical treatment, but among patients who receive surgery, urbanicity is not associated with extent of resection. These results point to potential differences in access to health care for those in nonmetropolitan areas that warrant further exploration.