Postoperative Venous Thromboembolism in Colon and Rectal Cancer: Do Tumor Location and Operation Matter?

BACKGROUND: Existing venous thromboembolism (VTE) risk scores help identify patients at increased risk of postoperative VTE who warrant extended prophylaxis in the first 30 days. However, these methods do not address factors unique to colorectal surgery, wherein the tumor location and operation performed vary widely. VTE risk may extend past 30 days. Therefore, we aimed to determine the roles of tumor location and operation in VTE development and evaluate VTE incidence through 90 days postoperatively. STUDY DESIGN: Adult patients undergoing surgery for colorectal cancer between January 1, 2005, and December 31, 2021, at a single institution were identified. Patients were then stratified by cancer location and by operative extent. VTEs were identified using diagnosis codes in the electronic medical record and consisted of extremity deep venous thromboses, portomesenteric venous thromboses, and pulmonary emboli. RESULTS: A total of 6,844 operations were identified (72% segmental colectomy, 22% proctectomy, 6% total (procto)colectomy), and tumor location was most commonly in the ascending colon (32%), followed by the rectum (31%), with other locations less common (sigmoid 16%, rectosigmoid junction 9%, transverse colon 7%, descending colon 5%). The cumulative incidence of any VTE was 3.1% at 90 days with a relatively steady increase across the entire 90-day interval. Extremity deep venous thromboses were the most common VTE type, accounting for 37% of events, and pulmonary emboli and portomesenteric venous thromboses made up 33% and 30% of events, respectively. More distal tumor locations and more anatomically extensive operations had higher VTE rates. CONCLUSIONS: When considering extended VTE prophylaxis after colorectal surgery, clinicians should account for the operation performed and the location of the tumor. Further study is necessary to determine the optimal length of VTE prophylaxis in high-risk individuals.