The Association Between Skeletal Muscle Mass and Surgical Site Infection and Prognosis in Patients Undergoing Free Flap Reconstructive Surgery for Oral Squamous Cell Carcinoma: A Single-Center, Retrospective Study.

[BACKGROUND/OBJECTIVES] Local and systemic factors, including nutritional status, influence the prognosis of oral squamous cell carcinoma (OSCC). Skeletal muscle mass (SMM) loss is a poor prognostic factor in older patients and those with cancer. Herein, we examined the SMM index (SMI), rates of surgical site infection (SSI), and prognosis of 92 patients (59 males and 33 females) who underwent resection and free flap reconstructive surgery (FFRS) between 2013 and 2021.

[METHODS] Preoperative computed tomography was performed to measure SMM at L3. The median SMI was 45.94 and 38.03 cm/m in males and females, respectively. Patients were classified into low and high SMI groups based on median SMI, and overall survival (OS) was analyzed.

[RESULTS] Overall, 47 (51.1%) and 45 (48.9%) patients had low and high SMIs, respectively. SSI occurred in 11 (12.0%) patients; wound dehiscence and delayed wound healing were observed in 22 (23.9%). SSI rates were not significantly different between the low and high SMI groups. Conversely, OS was significantly associated with age, pathological N (pN), extranodal extension (ENE), and SMI (high, 81.1%; low, 60.2%). Univariate analyses revealed significant associations between OS and age (≥65 vs. <65 years), SMI (low vs. high), pN (present vs. none), ENE (present vs. none), and albumin (<4.0 vs. ≥4.0 mg/dL). Cox multivariate analysis included SMI (low vs. high; hazard ratio [HR]: 2.339, 95% confidence interval [CI]: 1.008-5.429; = 0.015) and ENE (present vs. none; HR: 7.727, 95% CI: 3.083-19.368; < 0.001).

[CONCLUSIONS] SMI and ENE were identified as independent predictive factors of OS in patients with OSCC undergoing FFRS.