BACKGROUND: Venous thromboembolism is a well-recognized complication after hepatopancreatobiliary surgery. However, there is a paucity of nationwide data on risk factors and incidence within 1 year of surgery in patients undergoing hepatopancreatobiliary surgery. METHODS: This nationwide observational population-based cohort study used data extracted from all patients undergoing surgery for cancer surgery of the liver and the pancreas in France between 1 January 2015 and 31 December 2017. Estimation of 1 postoperative year cumulative incidence of venous thromboembolism and Cox proportional hazards model on 1-year global mortality were performed. RESULTS: During the study period, 16,960 patients underwent cancer surgery of the liver (n = 9,381) or pancreas (n = 7,579). The 90-day postoperative rate of venous thromboembolism was 6.1% (cancer surgery of the liver) and 6.7% (cancer surgery of the pancreas). Main risk factors of 90-day postoperative rate of venous thromboembolism were major hepatectomy (1.85
1.55-2.21), left pancreatectomy (1.45
1.18-1.79), presence of obesity (1.41
1.16-1.71), history of venous thromboembolism (4.58
3.41-6.14), open approach (1.31
1.06-1.62), and the occurrence of serious surgical complication (1.55
1.35-1.79). At 1 year, patients undergoing cancer surgery of the liver were at a lower risk of cumulative incidence (%) of venous thromboembolism compared with the cancer surgery of the pancreas group (P <
.001) (7.0
6.5-7.6 vs 9.8
9.1-10.4). Patients with venous thromboembolism within 1 year had greater risks of 1-year global mortality for each hepatopancreatobiliary surgery group: 3.58 (95% confidence interval, 3.02-4.23) and 3.97 (95% confidence interval, 3.40-4.63), respectively. CONCLUSION: Postoperative venous thromboembolism is a significant issue after hepatopancreatobiliary surgery, within 90 days postoperatively and up to 1 year, with the cancer surgery of the pancreas group being particularly at risk. A greater risk of global mortality within 1 year for patients experiencing early or late venous thromboembolism was found.