Association Between Temporalis Muscle Thickness and Risk of Disability and Mortality in Patients With Oral Cancer.

OBJECTIVE: To investigate the association between temporalis muscle thickness (TMT), an imaging-derived marker of muscle status, and disability and mortality outcomes in patients with oral cancer. METHODS: This retrospective cohort study included 527 patients with oral cancer treated at National Taiwan University Hospital between July 2012 and December 2021. TMT was measured on brain magnetic resonance imaging. Clinical factors associated with TMT were examined. Disability was assessed using the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0). The associations of TMT with disability and mortality were evaluated using multivariable logistic regression and Cox proportional hazards regression, respectively. RESULTS: The mean age of the participants was 54.7 ± 9.6 years, 96.2% were male, and the mean TMT was 6.3 ± 1.3 mm. Higher comorbidity burden, lower body mass index, unmarried status, higher Eastern Cooperative Oncology Group performance status, betel quid chewing, and reduced TMT were significantly associated with increased disability. After adjustment for covariates, higher TMT was independently associated with a lower risk of severe disability (Q4 vs. Q1: adjusted OR 0.38, 95% CI 0.17-0.80; p = 0.011; p for trend < 0.001). Higher TMT was also associated with a lower risk of all-cause mortality (adjusted HRs 0.44-0.54 across higher TMT quartiles). CONCLUSION: Reduced TMT was associated with greater disability and higher mortality risk in patients with oral cancer. These findings should be interpreted as exploratory associations and warrant further validation in prospective studies.