Evaluating the prognosis of oral squamous cell carcinoma patients via L3 skeletal muscle index

This study aimed to construct a formula to predict L3 skeletal muscle cross-sectional area (CSA) from C3 CSA and to select the cutoff values to evaluate the nutritional status in OSCC.A total of 220 OSCC patients in Nanfang Hospital were divided into two groups: the training set (n = 100) and the validation set (n = 120). Patients in the training set were performed the preoperative whole-body positron emission tomography-computed tomography (PET/CT) scans, and patients in the validation set received preoperative head-and-neck computed tomography (CT) scans. C3 CSA and L3 CSA were delineated. The predictive formula was established, and the gender-specific thresholds of malnutrition were obtained by X-tile software in training set. Finally, the formula and cutoff values were validated.The predictive formula was successfully established. The gender-specific cutoff values for L3 SMI were 55.0 cm2 /m2 for men and 36.6 cm2 /m2 for women. There were no differences between the overall survival (OS) of patients diagnosed with malnutrition and that of patients who are not malnutrition.Our studies reveal that the L3 CSA could be calculated by C3 CSA conveniently with our formula in OSCC, which allowed us to assess malnutrition with head-and-neck CT image. However, there is no direct connection found between malnutrition and OS in OSCC. Hence, further studies with a larger sample size may be required.