Delivering results and recommendations from a systematic review and meta-analysis of novel oral anticoagulants (NOACs) versus low molecular weight heparin (LMWH) in the prevention of venous thromboembolism (VTE) recurrence in cancer patients, Patricia Noreen Bueno, MD, from St Luke’s Medical Center in Quezon City, Philippines, asserted that the risk was “significantly lower” when using NOACs, but “careful consideration” must be employed when choosing an anticoagulant.
Presenting on the first morning of this year’s European Venous Forum (June 22–24) in Berlin, Germany, Bueno began by situating their chosen field of study, highlighting the prevalence of VTE as a common complication in cancer patients, and its association with higher morbidity and mortality.
“Traditionally,” she noted “LMWH has been the standard [preventive measure] in this population, however NOACs or oral anticoagulants have emerged as a potential alternative due to their convenience and ease-of-use.”
In their analysis, Bueno and her team looked at randomized controlled trials (RCTs) that included NOACs in patients with cancer-associated VTE, defining their primary outcome as VTE recurrence. To do so, they initiated a comprehensive search of clinical trials available on PubMed, Cochrane, Google Scholar and Gray literature, using RevMan 5.4 to perform their critical appraisal.
Identifying eight RCTs including 4,741 patients—2,408 who received NOACs and 2,337 who received LMWH—Bueno et al specify that NOACs were administered orally, while LMWH were required to be administered subcutaneously by a healthcare professional.
“Our analysis showed that risk of cancer-associated VTE recurrence was significantly lower in patients treated with NOACs, compared with LMWH [risk ratio 0.64; 95% confidence interval 0.52–0.80; p<0.0001; I2%],” Bueno said, however making clear that the safety of NOACs is not significantly superior to that of LMWH. Adding to their results, Bueno also noted that all-cause mortality showed no statistical difference between the two groups.
Showing consistency with prior meta-analyses performed in this area, Bueno conveyed that their review “[reflects] the benefits of NOACs’ pharmacokinetics and pharmacodynamics, including their short half-life, rapid onset/offset of action, and few drug-drug interactions”.
As an offshoot to their current study, Bueno then moved on to give detail to two subanalyses they performed using the present patient population, first looking at risk of major bleeding based on location of cancer and use of either NOACs or LMWH, and secondly, looking at the type of NOAC used, namely apixaban, rivaroxaban or edoxaban.
Elucidating the results of the former subanalysis, Bueno et al defined groups by gastrointestinal (GI) and non-GI location of cancer, finding no statistical significance between groups when using NOACs or LMWH. She continued, however, stating that in GI studies they found “an increased risk of major bleeding when [patients were] treated with NOACs.” This, she posited, may be due to cancer location and the presence of other pathologies such as ulceration, and “highlights the importance of closely monitoring symptoms and signs of bleeding in patients with GI malignancies while undergoing treatment with anticoagulants.”
Concerning the latter subanalysis, Bueno gave a brief review of available NOACs and their attributed risk factors—overall emphasizing the “careful consideration” that must be maintained by clinicians when choosing an appropriate anticoagulant—particularly for patients with pre-existing bleeding risk factors.
Overall, Bueno and her team observed that anticoagulation therapy with NOACs is “effective and safe” in preventing cancer-associated VTE recurrence. Although they acknowledge that the current preference is LMWH for patients with GI malignancies who have a high risk of bleeding, they hope that their review may “aid clinicians” in their decision-making and spur further clinical trials.
