S1230 Non-Vitamin K Oral Anticoagulants (NOACs) vs Low Molecular Weight Heparin (LMWH) for the Treatment of Venous Thromboembolism in the Setting of Gastrointestinal and Pancreato-Biliary Malignancies—A Meta-Analysis

Abstract

INTRODUCTION: The safety and efficacy of NOAC use compared with low molecular weight heparin (LMWH) use, the current standard of care for the treatment of gastrointestinal and pancreatobiliary cancer associated venous thromboembnolism (GI-CAVTE), has not been well studied. METHODS: A systematic review of Medline and Embase was conducted from inception to April 2020 to identify studies reporting the use of NOACs and LMWH for the treatment of GI-CAVTE. A meta-analysis of proportions as well as a comparative meta-analysis was performed to assess safety and efficacy. GI bleeding events were recorded and reported descriptively. RESULTS: Three observational studies enrolling 561 patients (213 on NOACs; 348 on LMWH) were found, 154 of whom were females. Pancreatobiliary malignancies were the most common in the NOAC group (N = 79), followed by gastric cancer (N = 41) and colorectal cancer (N = 21). In contrast, gastric cancer was the most common malignancy in the LMWH arm (N = 149), followed by pancreatobiliary malignancy(N = 135), and colorectal cancer (N = 11). The risk of bias as assessed by the ROBINS-I tool was moderate in 1 and serious in 2 studies. The OBR was 29% (23–35) with NOAC use, of which 28% (16–40%) were major bleeds and 81% (70-91%) were CRNMB. In contrast, the OBR with LMWH use was 20% (16–24%), of which 38% (26–49%) were major bleeds and 67% (56–78%) were CRNMB. Fatal bleeding events occurred in 7% (0–15%) of patients on NOACs and 9% (1–16%) of patients on LMWH. The risk of OBR was higher with NOAC use (RR 1.61; 1.19-2.19; I2 = 37.4%), as was the risk of CRNMB (RR 1.86; 1.27-2.72; I2 = 0%). However, no difference in major bleeding and fatal bleeding risk was found with NOAC versus LMWH use. Table 1 summarizes the reported gastrointestinal bleeding events across studies. The rVTE rate was 4% (1–6%) with NOAC use and 2% (1–4%) with LMWH use. There was no difference in the risk of rVTE, rDVT, rPE, or fatal VTE with NOAC versus LMWH use. CONCLUSION: NOACs may pose a greater risk of bleeding, particularly CRNMB, in patients with GI-CAVTE. We did not identify any signal of superior efficacy in term of rVTE, rDVT, or rPE risk with NOAC use compared with LMWH. The risk of bleeding from luminal malignancies while on NOACs remains to be studied further before any conclusions can be made. on Due to lack of randomized trials and a high number of observational studies, our findings are hypothesis generating at best, and further studies are needed to validate our findings.Table 1.: Reported Gastrointestinal Bleeding with DOAC and LMWH Use. CRNMB = Clinically relevant non-major bleeding; GI = gastrointestinalFigure 1.: Meta-Analysis of Proportions - Safety and Efficacy Endpoints - NOACs vs LMWH.Figure 2.: Comparative Meta-Analysis of Safety and Efficacy - NOAC vs LMWH.