[Clinical significance of prognostic nutritional index in patients with advanced gastric cancer].

OBJECTIVE: To investigate the relationship of prognostic nutritional index (PNI) with clinicopathological factors and the clinical significance of PNI in predicting the survival in patients with advanced gastric cancer. METHODS: Clinicopathological and follow-up data of 1150 patients with advanced gastric cancer who underwent radical gastrectomy from January 2007 to December 2010 at the Department of Gastrointestinal Surgery, Harbin Medical University Cancer Hospital were analyzed retrospectively. The PNI value was calculated [PNI=absolute value of lymphocyte(109/L)×5 + serum albumin (g/L)] and was grouped according to the mean value of PNI. Relationships of PNI with gender, age, tumor size, depth of invasion, tumor differentiation, tumor stage, tumor location, lymph node metastasis and tumor marker detection level were analyzed. At the same time, for the survival analysis of patients, log-rank method was used for univariate analysis, and Cox method was used for multivariate analysis. RESULTS: Of 1150 cases, 846 were males and 304 were females with an average age of 62 (24 to 88) years. The average maximum diameter of tumor was 5.4(1.0 to 20.0) cm. Tumor of 159 cases located in the gastric fundus, 221 cases in the gastric body, 705 cases in the gastric antrum and 65 cases in the whole stomach. Well differentiated tumors were found in 198 cases and poorly differentiated tumors in 952 cases. As for depth of tumor invasion, 165 cases were T2, 343 cases were T3 and 642 cases were T4. According to TNM stage, 53 cases were stage I(, 397 cases were stage II( and 700 cases were stage III(. The average lymph node metastasis rate was 25.0%, meanwhile lymph node metastasis was N0 in 296 cases, N1 in 246 cases, N2 in 277 cases and N3 in 331 cases. Blood examination showed hemoglobin ≤130 g/L in 544 cases and >130 g/L in 606 cases; carcinoembryonic antigen ≤5 µg/L in 903 cases and >5 µg /L in 247 cases; carbohydrate antigen 19-9 ≤37 kU/L in 927 cases and >37 kU/L in 223 cases. In whole patients, the mean value of PNI was 51.81(24.5 to 80.4), PNI ≤51.81 group had 563 cases, and PNI >51.81 group had 587 cases. Between PNI ≤51.81 group and PNI >51.81 group, age (χ2=22.661, P=0.000), tumor location (χ2=8.979, P=0.030), tumor size (χ2=34.509, P=0.000), tumor stage (χ2=11.644, P=0.003), depth of tumor invasion (χ2=21.681, P=0.000) and hemoglobin (χ2=112.262, P=0.000) were significantly different. Patients were followed up for an average of 45.1 months (4 to 108). The 5-year survival rate was 37.7% in PNI ≤51.81 group, while it was 47.0% in PNI >51.81 group, whose difference was statistically significant (χ2=8.326, P=0.004). Univariate analysis showed that patients with PNI ≤51.81(P=0.004), deeper tumor invasion (P=0.000), more metastatic lymph nodes (P=0.000), later TNM stage (P=0.000), lymph node metastasis rate >25.02%(P=0.000), hemoglobin ≤130 g/L(P=0.011), the maximum tumor diameter >5.4 cm (P=0.000), tumor undifferentiated (P=0.001), CEA >5 µg /L (P=0.000), CA199 >37 kU/L(P=0.000) and tumors locating in whole stomach (P=0.000) had poorer prognosis. Multivariate analysis showed that the age (HR=1.195, 95%CI: 1.019 to 1.401, P=0.028), the depth of tumor invasion(HR=1.429, 95%CI: 1.231 to 1.658, P=0.000), the number of metastatic lymph node (HR=1.536, 95%CI:1.330 to 1.774, P=0.000), the lymph node metastasis rate (HR=1.376, 95%CI:1.102 to 1.717, P=0.005), tumor TNM stage (HR=1.387, 95%CI: 1.026 to 1.876, P=0.033) and tumor size(HR=1.182, 95%CI: 1.005 to 1.390, P=0.043) were independent prognostic factors of gastric cancer patients, while PNI (HR=0.913, 95%CI: 0.774 to 1.076, P=0.278) was not an independent risk prognostic factor of gastric cancer patients. CONCLUSIONS: Although the PNI is not an independent risk factor of overall survival in patients with advanced gastric cancer, it is still an indicator of survival in patients with gastric cancer. Improving preoperative nutritional status in patients with gastric cancer may contribute to a better prognosis.