Efficacy and safety of short-term (3 days) enoxaparin in preventing venous thromboembolism after gastric cancer surgery: A single-center, prospective cohort study

Background: Pharmacologic prophylaxis such as enoxaparin for venous thromboembolism (VTE) is rarely used in Japan, even following abdominal cancer surgery, for which it is recommended in relevant guidelines (at least 7 days of use) along with mechanical prophylaxis with intermittent pneumatic compression. Reasons for enoxaparin's unpopularity include concerns over postoperative bleeding and its inconvenience in clinical practice. Here, we conducted a prospective clinical study of short-term (3 days) use of enoxaparin, which is considered to minimally impact postoperative management without increasing bleeding risk. Methods: Gastric cancer patients who underwent gastrectomy received enoxaparin for 3 days from postoperative day (POD) 1-4. The primary endpoint was the incidence of deep vein thrombosis (DVT), which was examined primarily via Doppler ultrasonography of the lower limbs between POD 8 and 14. The planned sample size was 70, which was calculated based on an estimated incidence rate of 9% and an upper limit of incidence rate of 20%, with alpha of 0.05 and beta of 0.2. Results: A total of 70 gastric cancer patients were enrolled, and ultimately, 68 patients received the protocol intervention and DVT evaluation. Sixty-seven patients completed 6 enoxaparin injections, but 1 patient did not complete the course due to abdominal bleeding after initiation. The incidence of DVT was 4.4% (3/68), and the 95% upper confidence interval was 12.2%, lower than the 20% threshold we set as the upper limit of DVT incidence. DVT was detected only in the peripheral veins of the lower extremities in all 3 affected patients. The incidence of bleeding-related complications, which were not severe, was 1.5% (1/68). Conclusions: Short-term (3 days) use of enoxaparin was shown to be effective and safe for VTE prophylaxis, comparable to regular use (at least 7 days), in postoperative management of gastric cancer surgery.