Objective: To describe the incidence of thromboembolic events (venous thromboembolism) before and after the diagnosis of epithelial endometrial cancer and to evaluate the effects of these events on survival.
Methods: We used the National Cancer Institute's Surveillance, Epidemiology, and End Results cancer registries linked to Medicare claim files to identify patients with epithelial endometrial cancer diagnosed between 1992 and 2009. To identify venous thromboembolism events 3 months before diagnosis and up to 24 months after diagnosis, we used International Classification of Diseases, 9th Revision, and Healthcare Common Procedure Coding System codes.
Results: A total of 23,122 patients were included; of them 1,873 (8.1%) developed a venous thromboembolism. Patients with low-grade (grades 1 and 2) endometrioid adenocarcinoma had a significantly lower rate of venous thromboembolism 3 months before and 6 months after the diagnosis of cancer (3.6%; 95% confidence interval [CI] 3.3-3.9%) compared with carcinosarcoma (9.2%; 95% CI 7.8-10.8%), clear cell (6.9%; 95% CI 4.8-9.7%), uterine serous cancer (8.1%; 95% CI 7.01-9.3%), and grade 3 endometrioid adenocarcinoma (6.1%; 95% CI 5.4-6.9%) (P<.001). On multivariate analysis during the same time period, most recent time periods of diagnosis, carcinosarcoma histology compared with lower grade endometrial cancer, higher stage, African American race, marital status, chemotherapy delivery, and lymph node dissection were associated with increased risk of venous thromboembolism. The median overall survival for women who experienced a venous thromboembolism 3 months before the diagnosis of endometrial cancer was 31 months (95% CI 20-48 months); in women diagnosed with venous thromboembolism 6 months after the cancer diagnosis was 37 months (95% CI 31-44), and in women who did not experienced a venous thromboembolism was 111 months (95% CI 109-114). After adjusting for prognostic factors, there was an association between venous thromboembolism diagnosed 3 months before endometrial cancer (hazard ratio 1.69, 95% CI 1.34-2.13) or 6 months after the diagnosis (hazard ratio 1.57, 95% CI 1.44-1.71) and lower survival.
Conclusion: Patients with uterine serous cancer, carcinosarcoma, clear cell carcinoma, and grade 3 endometrioid adenocarcinoma had a higher rate of venous thromboembolism than patients with low-grade endometrioid adenocarcinoma. A diagnosis of venous thromboembolism was associated with decreased survival in elderly patients with endometrial cancer.
Level of evidence: II.