Added prognostic value of temporal muscle thickness in glioblastoma with age-stratified analysis

To evaluate the prognostic value and age-stratified prognostic significance of temporal muscle thickness (TMT) in isocitrate dehydrogenase-wild type glioblastoma (GBM) based on the 2021 WHO central nervous system tumor classification. We retrospectively analyzed 285 patients with GBM treated between 2009 and 2022. Patients were subdivided into sarcopenic and non-sarcopenic groups based on the first quartile TMT value. Cox regression analysis was conducted to evaluate associations between overall survival (OS) and TMT, clinical characteristics, and molecular alteration status. Propensity score matching was conducted to control for the potential confounders. Age-stratified analyses of prognostic differences were conducted. In total, 285 patients (mean age = 59 years; standard deviation = 14; 242 males) were included. Multivariable Cox regression revealed that TMT was significantly associated with OS (Hazard ratio [HR], 1.42; 95% confidence interval (CI), 1.06-1.90; p = 0.02). Age (HR, 1.02; 95% CI, 1.01-1.03; p = 0.001), Karnofsky Performance Status (HR, 0.98; 95% CI, 0.97-0.99; p = 0.001), and mMGMT status (HR, 0.47; 95% CI, 0.35-0.63; p = 0.001) were also significantly associated with OS. In age- and sex-matched patients, TMT showed a significant association with OS (HR, 1.57; 95% CI, 1.09-2.28; p = 0.014). TMT inclusion in the multivariable Cox regression analysis model improved the concordance index from 0.685 to 0.706, with an age-dependent increase in its prognostic value (p = 0.01). TMT is an independent prognostic marker for OS in GBM, with its prognostic value increasing progressively with patient age.