American Society of Hirudotherapy

Comparing survival with vitamin K antagonists, low-molecular-weight heparin, and direct oral anticoagulants in patients with cancer-a systematic review and meta-analysis

Research article published in Research and practice in thrombosis and haemostasis (2025)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportClinical TrialsXirou V et al. · Research and practice in thrombosis and haemostasis, 2025

Abstract

BACKGROUND: Venous thromboembolism (VTE) is a frequent complication in malignancy. Low-molecular-weight heparins and direct oral anticoagulants have replaced vitamin K antagonists (VKAs) as the standard of care for cancer-associated VTE. Nonetheless, clinical trials have not established a survival benefit of these agents compared with VKA. OBJECTIVES: We conducted a systematic review and meta-analysis to compare survival in cancer patients receiving VKA vs other anticoagulants. METHODS: We searched Embase, Web of Science, PubMed, ClinicalTrials.gov, and Cochrane from inception until April 10, 2025, focusing on the use of VKA and non-VKA in cancer patients. Primary outcome was mortality and secondary outcomes included thromboembolism and bleeding. RESULTS: Of 11,198 studies screened, 14 studies (70,025 patients) were included. VKA were associated with lower mortality than non-VKA in observational studies (odds ratio [OR], 0.84; 95% CI, 0.78-0.91; I 2 = 81%; n = 6 studies) but not in randomized controlled trials (OR, 0.99; 95% CI, 0.86-1.13; I 2 = 0%; n = 8 studies). In subgroup analysis, follow-up period of >6 months (OR, 0.85; 95% CI, 0.79-0.92; I 2 = 75%), solid malignancies (OR, 0.81; 95% CI, 0.75-0.88; I 2 = 78%), and indication of VTE only (OR, 0.89; 95% CI, 0.83-0.96; I 2 = 42%) demonstrated improved survival with VKA. CONCLUSION: The use of VKA was associated with lower mortality than non-VKA anticoagulation in patients with cancer in observational studies but not in randomized trials. The analysis was limited by high heterogeneity, which must be considered when interpreting results.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article

Summary

Venous thromboembolism (VTE) is a frequent complication in malignancy. Low-molecular-weight heparins and direct oral anticoagulants have replaced vitamin K antagonists (VKAs) as the standard of care for cancer-associated VTE.

Why This Matters for Hirudotherapy

This systematic review and meta-analysis (14 studies, 70,025 cancer patients) compared survival across vitamin K antagonists, low-molecular-weight heparin, and direct oral anticoagulants for cancer-associated venous thromboembolism, finding lower mortality with VKAs in observational studies (OR 0.84) but no survival difference in randomized trials (OR 0.99). For ASH it documents how different anticoagulant classes are weighed in a thrombosis-prone population, the broad antithrombotic-management context within which the medicinal-leech secretome's natural anticoagulants are positioned. Honest caveat: the authors note high heterogeneity and a clear split between observational and randomized findings, so the apparent VKA benefit is not confirmed by RCTs; the analysis concerns systemic anticoagulant drugs and includes no data on, or mention of, leeches or hirudotherapy.

Citation

Comparing survival with vitamin K antagonists, low-molecular-weight heparin, and direct oral anticoagulants in patients with cancer-a systematic review and meta-analysis.

Xirou V et al. · Research and practice in thrombosis and haemostasis, 2025

Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026

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