NIMG-68. SARCOPENIA AS MEASURED BY TEMPORALIS MUSCLE WIDTH IS A PREDICTOR OF SURVIVAL IN PRIMARY CNS LYMPHOMA

Abstract

Sarcopenia refers to a loss of skeletal muscle mass, which has been associated with increased risk of injury and decreased ability to perform activities of daily living. In multiple cancers including systemic lymphomas, sarcopenia has been strongly associated with survival and may be an important way to risk stratify patients in clinical trials as well as routine practice. Temporalis muscle width has been reported as an indicator of sarcopenia and independent predictor of outcomes in multiple settings including glioblastoma, brain metastases and subarachnoid hemorrhage. We evaluated temporalis width in primary CNS lymphoma (PCNSL) patients at presentation and outcomes. Using an institutional database of immunocompetent PCNSL patients treated at the University of Washington, two independent readers reviewed the initial MRIs for 104 patients who presented from 2011-2021 and measured the width of the temporalis muscle on axial T1 images. Median duration of follow up was 42.2 months (range 0.59-125.9 months). Median age at diagnosis was 65 (range 19-90 years), and patients were 42.8% male, 57.2% female. Interrater variability was acceptable with an average intraclass correlation coefficient of 0.934. Temporalis measurements were normally distributed, with mean 0.79 cm and standard deviation 0.18 cm. We divided patients into two groups, those with temporalis width less than or greater than 1 standard deviation below the mean (absolute value 0.60 cm). Temporalis width was strongly associated with survival among all patients (χ2=15.5, p< 0.001) as well as patients 65 years or older (χ2=4.5, p=0.03). We conclude that sarcopenia as measured by temporalis muscle thickness is associated with survival in PCNSL and may be an important variable to consider in clinical trials and routine practice.