Abstract 17843: Direct Oral Anticoagulants versus Low Molecular Weight Heparin for Venous Thromboembolism in Cancer Patients: An Updated Systematic Review and Meta-Analysis

Introduction: Patients with cancer have an increased risk of venous thromboembolism (VTE). We aim to evaluate the risk of recurrent VTE and major bleeding in patients with cancer when started on DOACs versus low molecular weight heparin (LMWH).

Methods: We conducted a systematic literature search according to PRISMA guidelines to identify studies using the terms: “venous thromboembolism,” “low molecular weight heparin,” and “direct oral anticoagulants.” After the screening, We extracted the data until May 2023 in a data extraction sheet. Our inclusion criteria were: adult patients, and cancer patients, who were on DOACs or LMWH for VTE or atrial fibrillation. We used a variance-weighted random-effects model to analyze data on DOACs vs. LMWH, estimating event rates and odds ratios while assessing heterogeneity. Data were analyzed using the ‘meta’ package in R.

Results: Our analysis included 16 studies (n= 12216 patients). Cancer patients on DOACs significantly reduced the risk of recurrent VTEs compared to LMWHs OR 0.69 (95% CI: 0.56- 0.86, I 2:23% ). However, for major bleeding and clinically relevant non-major bleeding, although the statistical significance was not reached, a consistent trend favoring DOACs was observed (OR = 0.92, 95% CI: 0.65-1.30) and OR=1.19 (0.90-1.59) respectively. (Figure1)

Conclusions: Among cancer patients, DOACs are associated with a significantly lower risk of recurrent VTEs than LMWHs. Although the statistical significance was not reached for major bleeding and clinically relevant non-major bleeding, there was a trend favoring DOACs over VKA. Increased recruitment of cancer patients in clinical trials is needed to provide us with updated data to refine treatment strategies.