Combined Prognostic Value of Preoperative Temporal Muscle Thickness and Geriatric Nutritional Risk Index in Surgically Treated Head and Neck Squamous Cell Carcinoma

Background/Objectives: Temporal muscle thickness (TMT) has been proposed as a practical surrogate marker for skeletal muscle mass, whereas the geriatric nutritional risk index (GNRI) reflects nutritional status. However, the independent and combined prognostic value of TMT and GNRI in surgically treated head and neck squamous cell carcinoma (HNSCC) remains unclear. Methods: We retrospectively analyzed 214 patients with HNSCC who underwent curative-intent surgery. Disease-free survival (DFS) and overall survival (OS) were evaluated using Cox proportional hazards models. In the primary analyses, TMT and GNRI were entered simultaneously as continuous variables and adjusted for age, sex, clinical stage, and postoperative adjuvant treatment. For clinical interpretability, Kaplan–Meier analyses were additionally performed using a composite TMT–GNRI score. Results: In the multivariable analyses, higher TMT was independently associated with longer DFS (hazard ratio [HR] 0.83 per 1 mm increase, 95% confidence interval [CI] 0.72–0.96, p = 0.014) and OS (HR 0.73, 95% CI 0.60–0.89, p = 0.002). GNRI was significantly associated with DFS and OS in the univariate analyses; after simultaneous adjustment for TMT and clinical covariates, it remained independently associated with OS (HR 0.98 per 1-point increase, 95% CI 0.96–0.99, p = 0.015) and showed a borderline association with DFS (HR 0.984, 95% CI 0.966–1.001, p = 0.068). Kaplan–Meier analyses using the composite TMT–GNRI score demonstrated clear risk stratification, with the poorest outcomes observed in patients with concomitantly low TMT and low GNRI. Conclusions: In surgically treated HNSCC, preoperative TMT was independently associated with both DFS and OS. GNRI may provide additional prognostic information, particularly for OS.