Evaluation of rivaroxaban use in patients with gynecologic malignancies at an academic medical center: A pilot study.

BACKGROUND: Patients with gynecologic malignancies are at an increased risk for venous thromboembolism. National guidelines recommend treatment of an acute venous thromboembolism with low molecular weight heparin for 5-10 days followed by long-term secondary prophylaxis with low molecular weight heparin for at least six months. Non-vitamin K oral anticoagulants are not currently recommended to be used in cancer patients for the management of venous thromboembolism because robust data on their efficacy and safety have yet to become available in cancer patients. The objectives of this study were to determine the proportion of gynecologic oncology patients with venous thromboembolism using rivaroxaban compared to warfarin or low molecular weight heparin as well as compare the safety and efficacy of these anticoagulants.
METHODS: This study was a retrospective pilot analysis of adult patients with gynecologic malignancies who received either rivaroxaban, warfarin or low molecular weight heparin for treatment of venous thromboembolism at Augusta University Medical Center from 1 July 2013 to 30 June 2015. Statistical comparisons between the enoxaparin and rivaroxaban group were made using T-tests and Chi-square or Fisher's exact tests, where appropriate.
RESULTS: Out of the 49 patients, 37% (18) patients were on rivaroxaban, 53% (26) on enoxaparin, and 10% (5) on warfarin. Only one patient (4%) in the enoxaparin group experienced a recurrent deep vein thrombosis while there were no cases of recurrent venous thromboembolism in the rivaroxaban and warfarin group. The incidence of major bleeding was 17% (n = 2), 20% (n = 1), and 8% (n = 2) in patients receiving rivaroxaban, enoxaparin, and warfarin, respectively. The rate of switching to a different anticoagulant than originally prescribed was 42% (n = 14) in the enoxaparin arm, and 5.5% (n = 1) in the rivaroxaban arm.
CONCLUSION: A high proportion of our gynecologic oncology patients received rivaroxaban for the management of venous thromboembolism. The sample size of this pilot analysis was too small to draw any conclusions regarding efficacy and safety of rivaroxaban compared with enoxaparin and warfarin. High rate of rivaroxaban use in gynecologic oncology patients at our institution highlights the need for larger, well-designed randomized controlled trials to confirm the safety and efficacy of its use in this population.