Background:Gastric cancer is the 2nd most common cause of cancer-related deaths,and the morbidity rate after surgery is reported to be as high as 46％.The estimation of possible complications,morbidity,and mortality and the ability to specify patients at high risk have become substantial for an intimate follow-up and for proper management in the intensive care unit.This study aimed to determine the prognostic value of the preoperative platelet-to-lymphocyte ratio(PLR)and neutrophil-to-lymphocyte ratio(NLR)and their relations with clinical outcomes and complications after gastrectomy for gastric cancer.Methods:This single-center,retrospective cohort study evaluated the data of 292 patients who underwent gastrectomy with curative intent between January 2015 and June 2018 in a tertiary state hospital in Ankara,Turkey.A receiver operating characteristic curve was generated to evaluate the ability of laboratory values to predict clinically relevant postoperative complications.The area under the curve was computed to compare the predictive power of the NLR and PLR.Then,the cutoff points were selected as the stratifying values for the PLR and NLR.Results:The area under the curve values of the PLR(0.60,95％CI 0.542-0.657)and NLR(0.556,95％CI 0.497-0.614)were larger than those of the other preoperative laboratory values.For the PLR,the diagnostic sensitivity and specificity were 50.00％and 72.22％,respectively,whereas for the NLR,the diagnostic sensitivity and specificity were 37.50％and 80.16％,respectively.The PLR was related to morbidity,whereas the relation of the NLR with mortality was more prominent.This study demonstrated that the PLR and NLR may predict mortality and morbidity via the Clavien-Dindo classification in gastric cancer patients.The variable was grade ≥3 in the Clavien-Dindo classification,including complications requiring surgical or endoscopic interventions,life-threatening complications,and death.Both the PLR and NLR differed significantly according to Clavien-Dindo grade ≥3.In this analysis,the PLR was related to morbidity,while the NLR relation with mortality was more intense.Conclusion:Based on the results of the study,the PLR and NLR could be used as independent predictive factors for mortality and morbidity in patients with gastric cancer.