OC 25.5 - The Incidence and Risk Factors of Venous and Arterial Thrombosis in Ovarian Cancer Patients- Results from a Population Database

Background: Ovarian cancer (OC) patients are at high risk of thromboembolism due to the hypercoagulable state of malignancy. While this association has been well studied regarding venous thromboembolism (VTE), there is a lack of evidence regarding the risk of arterial thromboembolism (ATE). It is also unknown if other risk factors for thrombosis are involved. Appropriate identification of patients at high risk enables more targeted, effective and safe thromboprophylaxis.

Aims: To determine the incidence of thromboembolism in patients with OC from a Canadian population and evaluate the role of risk factors other than cancer.

Methods: We analysed comorbidities and incidence of thromboembolic events in a retrospective cohort study of all patients diagnosed with epithelial OC between January 1996, and December 2017, in British Columbia, Canada. The study was conducted using medical records obtained from PopDataBC, a de-identified health record database. VTE, ATE and comorbidities in medical records were identified using ICD-9-CM and ICD-10-CM codes. The presence of comorbidities was compared between cancer patients who developed VTE or ATE and those who did not. Statistical analysis was performed using Chi-squared test or Fishers exact test in cases where cell counts were < 5 patients. A p-value < 0.05 was considered significant.

Results: Of 4,491 patients with epithelial OC (mean age of 61.4 years), 1.36% experienced ATE and 6.75% experienced VTE. Mean follow-up time was 5.76 years. Sepsis was significantly associated with both VTE and ATE (table 1). Top four risk factors for ATE were: sepsis, peripheral vascular disease, open wound and intracranial injury. The occurrence of ATE and VTE was significantly associated with overall mortality (table 2).

Conclusion(s): Risk factors predicting thromboembolic events in OC patients are not consistent between both ATE and VTE. Thrombosis risk assessment is needed to reduce thrombosis occurrence and improve quality of care in this cohort.