Objective: To determine the effect of switching from the initial direct oral anticoagulant (DOAC) to another DOAC on exacerbation of deep vein thrombosis (DVT).

Materials and Methods: We retrospectively reviewed the data of patients with advanced cancer who experienced exacerbated DVT during initial treatment with DOAC due to new venous thromboembolism (VTE). After switching to another DOAC for VTE recurrence, changes in the thrombus and bleeding were evaluated for 3 months. Eighteen patients met these criteria. We compared the effect of anticoagulant switching on the switched-drug group in those 18 patients with the effect of no anticoagulant switching on the single-drug group of patients (n=78) with a similar background.

Results: The recurrence rate of VTE in the switched-drug group was 6%. Non-major bleeding occurred in 11% of patients. Recurrent VTE occurred in 6% of patients in both the switched-drug and single-drug groups, respectively [risk ratio (RR): 0.9, 95% confidence interval (CI): 0.11–7.6]. Non-major bleeding occurred in 11% and 14% of patients in the switched-drug and single-drug groups, respectively (RR: 0.79, 95%CI: 0.19–3.2).

Conclusion: Switching DOAC may be a treatment option for exacerbation of DVT in patients with advanced cancer.