Incidence of venous thromboembolism (VTE) in ovarian cancer patients on low dose aspirin (312)

Abstract

<b>Objectives:</b> Patients with ovarian cancer are at high risk for malignancy- associated venous thromboembolism (VTE). Recent guidelines recommend anticoagulation with low molecular weight heparin (LMWH) or direct oral anticoagulant (DOAC) for high-risk patients receiving chemotherapy. Neither of these medications is ideal owing to the route of administration and cost, respectively. Aspirin has been suggested as a possible low-cost, easily administered alternative to LMWH and DOAC for VTE prophylaxis. The goal of our study was to examine the association between aspirin use and the rate of VTE in ovarian cancer patients. <b>Methods:</b> A single-institution retrospective study was conducted among patients diagnosed with epithelial ovarian cancer between 2005 and 2020. The primary exposure of interest was aspirin use at diagnosis. The outcome of interest was VTE incidence during treatment. Demographic and clinical data were abstracted from the electronic medical record. Descriptive statistics and t-tests, Chi-square, and Fisher's exact tests were used to analyze and compare clinical variables. A multivariable analysis was performed with multiple logistic regression, controlling for age, stage, BMI, and histology. Statistical significance was set at p=0.05. <b>Results:</b> A total of 201 patients with ovarian cancer were included in this study. The median age was 59 years. Most women underwent primary cytoreduction (87%) via laparotomy (83%), and 78% achieved optimal cytoreduction. Within this cohort, 39 (19.4%) women were taking daily aspirin at the time of diagnosis. VTE after diagnosis was observed in a total of 32 (15.9%) women. Of those who were taking aspirin at diagnosis, seven (21.9%) developed VTE, compared to 25 (15%) in the control group (p = 0.7). Aspirin is not independently associated with VTE (OR: 0.81, 95% CI: 0.32-2.25). Most VTEs were diagnosed during adjuvant treatment (43.8%). There were no statistically significant differences in histology, stage, surgery type, rate of optimal debulking, or time to finish adjuvant therapy between women who developed VTE versus those who did not. On multivariable analyses, neither ASA status nor high-grade serous histology was associated with VTE (OR: 1.09, 95% CI: 0.48-2.49; and OR: 0.81, 95% CI: 0.32-2.25, respectively). It should be noted that the timeframe studied included low rates of neoadjuvant therapy. <b>Conclusions:</b> In line with previous reports, nearly 16% of this cohort developed VTE in association with an ovarian cancer diagnosis. VTE rate among women using aspirin was not different from those not on aspirin. While limited by sample size, our data suggest that aspirin alone appears insufficient for prophylaxis against VTE in women with ovarian cancer.