Higher incidence of venous thromboembolism associated with increasing lines of treatment in heavily treated ovarian cancer patients

Objective: Ovarian cancer is associated with a high rate of venous thromboembolism. Our objective is to report the incidence of venous thromboembolism in recurrent ovarian cancer, assess the impact on morbidity and mortality, and evaluate predictors of venous thromboembolism.

Methods: A retrospective single institution cohort study was performed. Patients with a diagnosis of recurrent ovarian cancer between 2007 and 2020 and no previous history of venous thromboembolism were identified. Demographic and clinical variables were collected. Univariate and multivariable analyses were performed to identify predictors of venous thromboembolism.

Results: Of the 345 patients included in this study, 77 (22.3%) developed a venous thromboembolism. Most (n=56, 72.7%) were actively receiving treatment at the time of diagnosis of venous thromboembolism, of whom 44 (78.6%) had received three or more lines of treatment. In total, 42 (54.5%) were admitted to hospital on diagnosis and one mortality (1.3%) occurred secondary to venous thromboembolism. An intermediate/high risk Khorana score was not predictive of venous thromboembolism (p=0.24). The risk of venous thromboembolism was significantly higher with increasing lines of chemotherapy (odds ratio 1.14, 95% confidence interval 1.02 to 1.28 per line, p=0.026). There was no significant difference in overall survival (62.9 vs 49.1 median months, p=0.29) between patients with and without venous thromboembolism.

Conclusions: More than 20% of patients with recurrent ovarian cancer developed a venous thromboembolism, and most occurred after three or more lines of treatment. The risk of venous thromboembolism was higher with increasing lines of chemotherapy. While venous thromboembolism did not appear to impact survival in this population, nearly half required hospitalization, emphasizing the morbidity of venous thromboembolism and potential impact on healthcare costs. Further studies are needed to improve risk stratification for venous thromboembolism in this high risk population.