Preoperative D‑dimer level and prognosis in patients diagnosed with gastric cancer and undergoing gastric cancer radical surgery: A retrospective cohort study

Gastric cancer, one of the most aggressive tumors affecting the digestive tract, has seen a rise in both incidence and mortality rates in recent years, with a lack of clear prognostic indicators. D-dimer, a byproduct of fibrin degradation, is a conventional coagulation biomarker that has been investigated as a potential adverse prognostic factor for postoperative cancer patients. However, conflicting results exist, with some studies suggesting that D-dimer is an independent risk factor for the postoperative prognosis of gastric cancer, and others suggesting that there is no significant association between D-dimer level and gastric cancer prognosis. This controversy underscores the need for further research to determine the true influence of D-dimer level on the prognosis of postoperative cancer patients, including exploring the linear and non-linear associations, and identifying optimal critical values before surgery. The present study aimed to assess the association between preoperative D-dimer levels and 5-year overall survival (OS) rate in patients undergoing radical surgery for gastric cancer. Data was analyzed from patients diagnosed with gastric cancer who underwent a radical gastrectomy at Shanxi Cancer Hospital (Taiyuan, China) in 2017 and were followed up for 5 years until December 2022. Preoperative D-dimer levels and tumor-related indicators were collected as covariates from hospital records, with patient follow-up information obtained from the hospital's tracking system. Utilizing multivariate Cox regression, curve fitting and inflection point analysis, the present study sought to investigate the link between preoperative D-dimer levels and 5-year OS rate following radical surgery for gastric cancer. After strict admission and exclusion procedures, a total of 133 patients were included in the study and were then classified based on D-dimer level. Based on the mean value, the D-dimer levels were segregated into two distinct cohorts: The D-dimer_high group (n=66) and the D-dimer_low group (n=67). Cox multiple regression analysis was conducted using both continuous and binary variables. The results showed no effect in terms of the continuous variables, but higher preoperative D-dimer levels were significantly associated with a higher 5-year overall survival compared with lower preoperative D-dimer levels in the categorical variables. Therefore, curve fitting was performed, which indicated that the association between D-dimer level and 5-year survival rate after radical gastrectomy for cancer showed a U-shaped curve, with P<0.001, high and low D-dimer levels both indicated poorer prognosis. A curvilinear correlation was demonstrated between preoperative D-dimer levels and the 5-year survival rate following radical gastrectomy for cancer. Subsequently, an inflection point analysis found that the inflection point was located at 100-200 ng/ml. In conclusion, in patients undergoing radical gastrectomy for gastric cancer, preoperative D-dimer can be used to indicate the current state of the tumor to some extent through blood coagulation status. Notably, a U-shaped association exists between D-dimer levels and 5-year postoperative survival rate in gastric cancer. This association demonstrates varying effects across different intervals. Specifically, D-dimer levels <100 ng/ml are associated with a worse prognosis, whereas levels >200 ng/ml are associated with a better prognosis.