Prospective Study on the Incidence of Postoperative Venous Thromboembolism in Korean Patients with Colorectal Cancer

Pharmacologic thromboprophylaxis is routinely recommended for Western cancer patients undergoing major surgery for prevention of venous thromboembolism (VTE). However, it is uncertainwhetherroutine administration of pharmacologic thromboprophylaxis is necessary in all Asian surgical cancer patients. This prospective study was conducted to examine the incidence of and risk factors for postoperative VTE in Korean colorectal cancer (CRC) patients undergoing major abdominal surgery.This study comprised two cohorts, and none of patients received perioperative pharmacologic thromboprophylaxis. In cohort A (n=400), patients were routinely screened for VTE using lower-extremity Doppler ultrasonography (DUS) on postoperative days 5-14. In cohort B (n=148), routine DUS was not performed, and imaging was only performed when there were symptoms or signs that were suspicious for VTE. The primary endpoint was the VTE incidence at 4 weeks postoperatively in cohort A.The postoperative incidence of VTE was 3.0% (n=12) in cohort A. Among the 12 patients, eight had distal calf vein thromboses and one had symptomatic thrombosis. Age ≥ 70 years (odds ratio [OR], 5.61), ≥ 2 comorbidities (OR, 13.42), and white blood cell counts of > 10,000/μL (OR, 17.43) were independent risk factors for postoperative VTE (p < 0.05). In cohort B, there was one case of VTE (0.7%).The postoperative incidence of VTE, which included asymptomatic cases, was 3.0% in Korean CRC patients who did not receive pharmacologic thromboprophylaxis. Perioperative pharmacologic thromboprophylaxis should be administered to Asian CRC patients on a risk-stratified basis.