Low molecular weight heparin (LMWH) has been widely used to prevent venous thromboembolism in cancer surgical patients. However, relatively few studies have examined the safety aspects related to the use of LMWH after abdominal cancer surgery. This study was designed to investigate the relationship between bleeding complications and LMWH thromboprophylaxis after gastric cancer surgery.

From March to July in 2009, 179 consecutive patients who underwent gastric cancer surgery at our institution were administered LMWH (3200 U once daily from 2 to 6 h before surgery until discharge) perioperatively. A total of 182 patients consecutively treated before the introduction of LMWH prophylaxis were selected as controls.

There were 234 men and 127 women (mean age, 60 ± 12 years). No significant intergroup differences were observed with respect to clinicopathological features and operative procedures. No patient in the LMWH or control group developed symptomatic venous thromboembolism postoperatively. However, the LMWH group had a significantly higher surgical complication rate (27.4 versus 15.4%, P = 0.005). Among the surgical complications, postoperative bleeding and wound complications were significantly higher in the LMWH group, whereas other complications were similar in the two study groups. Multivariate analysis showed that LMWH administration was an independent risk factor (odds ratio, 2.83; 95% confidence interval, 1.28–6.23, P = 0.009) of postoperative bleeding.

LMWH thromboprophylaxis was found to increase significantly the risk of bleeding complications after gastric cancer surgery. Optimal LMWH prophylaxis regimens, including the dosage and timing of treatment commencement, for gastric cancer surgery should be determined in further clinical trials.