Objective  To investigate the value of postoperative prognostic nutritional index (PNI) in predicting prognosis of oral squamous cell carcinoma (OSCC) patients initially undergoing radical operation.

  Methods  Clinical and follow-up materials of 437 OSCC patients initially undergoing radical operation in the Ninth People's Hospital Affiliated to Medical School of Shanghai Jiaotong University from January 2015 to October 2017 were retrospectively analyzed. PNI was calculated according to the blood routine results one week before surgery. The Youden index was calculated by receiver operating characteristic (ROC) curve, and PNI with the maximum Youden index was selected as the optimal critical value for predicting the prognosis of OSCC. The relationship between preoperative PNI and clinical characteristics was analyzed. Kaplan-Meier survival analysis and Cox regression analysis were conducted to analyze the influence of PNI on prognosis of patients with OSCC.

  Results  The mean value of preoperative PNI was (49.93±5.60) and the optimal critical value of PNI was 46.23. Preoperative PNI was associated with age (P < 0.001), T staging (P < 0.001) and TNM staging (P=0.013). The 3-year survival rate of patients in the high PNI group was 84.7%, which was significantly higher than 57.3% in the low PNI group (P < 0.001). Multivariate analysis showed that aged over 60 years old (HR=2.211, 95% CI, 1.390 to 3.518, P=0.001), stage Ⅲ and Ⅳ of TNM (HR=3.911, 95% CI, 2.561 to 6.221, P < 0.001) and PNI ≤46.23 (HR=2.554, 95% CI, 1.707 to 3.821, P < 0.001) were the independent risk factors of prognosis in patients with OSCC.

  Conclusion  Preoperative low PNI is an independent risk factor for the prognosis of patients with OSCC, which has a certain guiding significance for the prognosis evaluation of OSCC.