Perioperative lymphocyte-to-monocyte ratio changes plus CA199 in predicting the prognosis of patients with gastric cancer

Background: This study aimed to investigate the value of perioperative lymphocyte-to-monocyte ratio (LMR) changes in predicting postoperative survival among patients undergoing radical gastrectomy, and explore whether the combination of preoperative carbohydrate antigen 199 (CA199) and LMR changes would further improve the prognostic accuracy. Methods: A total of 456 patients who underwent radical gastrectomy at the Affiliated Hospital of Nantong University were included as the training set, and 210 patients from the Nantong Tumor Hospital were enrolled as the validation set. The patients' peripheral complete blood counts, including lymphocytes, monocytes, and tumor marker CA199 level, were checked regularly in all patients 1 week before and after radical gastrectomy by two technicians who were blinded to their clinical characteristics. The LMR was calculated by dividing the lymphocyte count by the monocyte count in the peripheral blood. (LMR)-L-Delta could be obtained by subtracting the preoperative LMR from the postoperative LMR. The serum CA199 level was determined through a latex immunoassay (Mitsubishi Chemical Ltd., Japan). The survival curve was drawn according to the Kaplan-Meier method, and variables with P<0.05 in univariate analyses were transferred to multivariate Cox regression analysis. A nomogram was constructed using the finalized separated prognostic factors of gastric cancer (GC). The main prognostic indicator was overall survival (OS). Results: In the training and validation sets, the prognostic predictive ability of CA199 and (LMR)-L-Delta (postoperative LMR minus preoperative LMR) was independently evaluated (both P<0.05). (LMR)-L-Delta and CA199 were used to establish the (LMR)-L-Delta-CA199 score. The results showed that the higher the (LMR)-L-Delta-CA199 risk score, the worse the prognosis, especially in patients with advanced GC. Postoperative adjuvant chemotherapy improved the long-term prognosis of patients with a (LMR)-L-Delta-CA199 score of 1 but had no significant effect on the survival rate of patients with 0 and 2 points. Conclusions: (LMR)-L-Delta-CA199 can better predict the long-time survival of patients with GC. In addition, it can also predict the response of postoperative adjuvant chemotherapy in patients with GC.