# Temporalis Muscle Thickness as a Prognostic Factor for 30-Day, 90-Day, and Overall Mortality in Newly Diagnosed Glioblastoma

## TL;DR

This study shows that measuring temporal muscle thickness can predict survival outcomes in patients with glioblastoma, independent of other factors.

## Contribution

The study demonstrates that sarcopenia, measured by temporalis muscle thickness, is an independent prognostic factor for mortality in glioblastoma patients.

## Key findings

- Sarcopenia predicted 30-day mortality after surgery in GBM patients.
- The most sarcopenic patients had higher 90-day and overall mortality.
- Sarcopenia compared favorably to other known mortality predictors in GBM.

## Abstract

Background: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Accurate prognostic biomarkers are needed to guide care and treatment pathways across the spectrum of age. Temporal muscle thickness (TMT) is an accessible parameter that has been recognized as a prognostic marker for GBM. In addition, frailty, as measured by sarcopenia, has been proven to predict overall survival in other oncologic processes.

Objective: We evaluated whether sarcopenia, as measured by temporalis muscle thickness, has prognostic value for predicting survival in GBM. We aimed to confirm its prognostic accuracy and compare it to other survival markers.

Methods: A prospective GBM database identified 257 patients undergoing initial diagnostic surgery at Henry Ford Hospital in Detroit, Michigan. Sarcopenia was quantified by temporalis muscle thickness and grouped into tertiles. Mortality hazard ratios were calculated using multivariate analysis.

Results: After multivariate analysis, sarcopenia at the time of initial surgery was the only factor associated with mortality at 30 days postoperatively (OR 0.10, P = 0.030). Analysis demonstrated that mortality at 30 days had no association with gender, past medical history, tumor focality, tumor volume, tumor eloquence, or extent of resection. Sarcopenia at initial surgery predicted 90-day postoperative mortality; the most sarcopenic patients (first tertile) had greater mortality than those in the second (OR 0.28, P = 0.021) and third tertiles (OR 0.04, P = 0.003). Sarcopenia predicted overall mortality, greater in the first tertile than the second (OR 0.41, P < 0.001) and third tertiles (OR 0.41, P < 0.001). Sarcopenia compared favorably to other predictors of mortality, including initiation of postoperative temozolomide and radiation treatment (OR 0.27, P < 0.001), gross total resection (OR 0.54, P = 0.007), and O6-methylguanine-DNA methyltransferase (MGMT) methylation status (OR 0.44, P < 0.001). Kaplan-Meier survival curves represent differences in survival (log-rank p < 0.001).

Conclusions: Sarcopenia has prognostic value for predicting postoperative 30-day, 90­-day, and overall survival from diagnosis in GBM. The frailty/sarcopenia paradigm is independent of patient demographic, oncologic, genetic, surgical, and therapeutic factors. Temporalis muscle thickness assessment provides a simple method to help guide treatment decisions in affected adult populations.