Low-molecular-weight heparin in cancer-associated thrombosis: treatment, secondary prevention, and survival

Abstract

Objectives. Venous thromboembolism (VTE) occurs more frequently in cancer patients than in non-cancer patients and outcomes are poor in patients with both cancer and thrombosis. Patients with cancer who develop thrombosis are more likely to experience a recurrence of VTE and have increased bleeding complications while receiving oral anticoagulant treatment. The purpose of this paper is to discuss the causes and outcomes of thrombosis in cancer patients, the limitations of warfarin therapy, the guidelines and data for the use of low-molecular-weight heparins (LMWHs) in the treatment and secondary prevention of thrombosis in cancer patients, and emerging data regarding survival with the use of LMWH in cancer patients. Methods. Literature for this paper has been collected using multiple sources, including primary, secondary, and tertiary references. Online searches have been conducted utilizing the PubMed and OVID databases, and abstracts from the Proceedings of the American Society of Clinical Oncology and the American Society of Hematology Annual Meeting and Exhibition. The following key terms were used in the search: cancer, deep vein thrombosis, pulmonary embolism, anticoagulation, LMWHs, guidelines, survival, cost. Results. The long-term use of LMWHs in the settings of cancer and thrombosis are supported by recent clinical trial evidence that demonstrate their equivalent safety and improved efficacy when compared to oral anticoagulants resulting in their inclusion in current guidelines. Finally, newer studies offer further evidence of improved outcomes with dalteparin and nadroparin, including possible survival benefits. Conclusions. Treatment with LMWHs has been shown to be more effective than warfarin in the extended treatment of VTE in patients with cancer and is safe in this setting. Use of a LMWH for at least the first 3–6 months of long-term treatment is now considered the standard of care for patients with cancer and is recommended in numerous guidelines. Additionally, further evaluation of the survival benefits of LMWH in cancer patients is warranted.