Clinical Study Of PNI Predicting Long-term Postoperative Survival Of Diffuse Gastric Cancer

Objective: TNM stage is closely related to the prognosis of patients,but the prediction of long-term postoperative survival is relatively inadequate.Prognostic nutrition index（PNI）represents the preoperative nutritional and immune status of patients,and is associated with the prognosis of some patients with malignant tumor,but its relationship with diffuse gastric cancer（DGC）is unclear.This study investigated the predictive value of PNI for long-term survival after DGC.Methods: Clinical records and long-term follow-up data of 353 patients with DGC background in a single center were retrospectively collected to calculate the optimal cut-off value of PNI（5× preoperative lymphocyte count（10^9/L）+preoperative serum albumin（g/L））.The 1-year,3-year,5-year survival rate and median survival time of patients were compared according to the optimal PNI cut-off value grouping.Cox regression was used to analyze the independent predictors of long-term survival after DGC,and kaplan-Meier method was used to analyze the influence on survival and prognosis of patients,and Nomgram prediction model was constructed.Results: The optimal cut-off value of PNI was 50.1.Patients with high PNI（≥50.1）had higher 1-year,3-year and 5-year survival rate and longer median survival time（P < 0.05）.Multivariate COX regression analysis found that PNI（HR:1.911,95%CI: 1.303-2.802,P=0.001）,maximum tumor diameter（HR: 0.477,95%CI: 0.344-0.663,P<0.001）,TNM stage（HR: 0.477,95%CI: 0.344-0.663,P<0.001）: 1.861,95%CI: 0.184-0.66,P<0.001),CEA（HR: 1.691,95%CI:1.175-2.432,P=0.005）were independent predictors of postoperative long-term survival in patients with DGC.The Nomogram prediction model was constructed based on the above indicators,and the calculated model consistency index（C-index）was 0.720（95%CI: 0.682-0.758）.The 1-year,3-year and 5-year survival rate calibration charts showed good fit,and the decision curve Showing that the net benefit of patients ranged from 16% to 79%,the model has a high degree of discrimination,calibration and clinical utility..Conclusions:The optimal cut-off value of PNI was 50.1,and the patients with high PNI（≥50.1）had better prognosis;PNI,TNM stage,maximum tumor diameter,and CEA were all independent predictors of postoperative long-term survival;the Nomogram prediction model constructed based on PNI has higher discrimination,calibration and clinical practicability.