Efficacy and safety of primary thromboprophylaxis in adult ambulatory cancer patients: A scholarly review.

Abstract

e24003 Background: Venous thromboembolism (VTE) is a major complication in patients with cancer, with approximately a six-fold increased risk compared to the general population. VTE contributes significantly to morbidity and mortality, particularly in the ambulatory setting, where risk assessment and monitoring are more complex. Primary thromboprophylaxis has been shown to reduce VTE incidence but is associated with an increased risk of bleeding. Patients with cancer are subject to significant treatment burdens, both in terms of anticancer and supportive therapy. This review aimed to evaluate the efficacy and safety of primary thromboprophylaxis in adult ambulatory cancer patients, with a particular focus on VTE incidence, major bleeding, and mortality or survival outcomes. Methods: A systematic literature search was conducted across the PubMed, MEDLINE, and Embase databases for studies published between January 1, 2014, and November 14, 2024. Eligible studies were randomised controlled trials involving adult cancer patients (≥18 years) receiving primary thromboprophylaxis in the ambulatory setting. The primary outcome was VTE incidence. Secondary outcomes included major bleeding rates, mortality, and survival outcomes. Study quality was assessed using the National Health and Medical Research Council levels of evidence, the Cochrane Risk of Bias tool, and the Revised Joanna Briggs Institute Critical Appraisal tool. Results: Nine randomised controlled trials were selected for final analysis. Thromboprophylaxis significantly reduced VTE incidence in six of the trials, using either low molecular weight heparin (LMWH) or a direct oral anticoagulant (DOAC). Three studies reported significantly higher major bleeding rates associated with thromboprophylaxis, particularly with DOACs. Eight studies demonstrated no significant differences in mortality or survival outcomes between thromboprophylaxis and control groups. One biomarker-guided trial reported a reduction in short-term mortality with LMWH, but this finding was not consistently replicated. Conclusions: Primary thromboprophylaxis in ambulatory adult cancer patients effectively reduces VTE incidence but increases the risk of major bleeding and does not consistently improve mortality or survival outcomes. These findings highlight the importance of individualised risk assessment and careful patient selection. Future large-scale multicentre randomised trials with broader inclusion criteria, longer follow-up, and improved risk stratification tools are needed to optimise the balance between efficacy and safety in thromboprophylaxis for ambulatory cancer patients.