(ChemotherapyAdvisor) – First-line use of low molecular weight heparin (LMWH) monotherapy for cancer-associated venous thromboembolism (VTE) increased steadily between 2000 and 2007, yet this evidence-based treatment remains underutilized, a study published in The Oncologist online February 14 concluded.

Patients with an inpatient/outpatient VTE diagnosed within two years of advanced lung, prostate, colon, or breast cancer and an outpatient purchase of warfarin, LMWH, and/or fondaparinux anticoagulant within seven days of VTE diagnosis were identified using electronic health records from four HMOs. “First-line outpatient VTE pharmacological treatment and factors independently associated with receipt/non-receipt of LMWH monotherapy were assessed,” the investigators wrote.

LMWH monotherapy was found to be the primary VTE treatment in 25% of 1,089 eligible patients; 74% received warfarin-based therapy. Overall, percentage use of LMWH increased from 18% in patients diagnosed in 2000 to 31% in 2007. Factors associated with LMWH monotherapy were year of diagnosis of VTE, administration of chemotherapy within 60 days preceding VTE diagnosis, history of VTE prior to a diagnosis of cancer, and invasive surgery within 90 days of VTE diagnosis.

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Patients who had colorectal and prostate cancers were less likely than those with lung cancer to be treated with LMWH monotherapy, as were patients with stage III vs. stage IV disease.

“Future studies should explore reasons underlying the underutilization of this preferred evidence-based treatment as well as the comparative effectiveness of LMWH versus warfarin-based anticoagulation in real-world cancer patients with VTE,” the authors noted. Reasons may include physician comfort with warfarin, which has a long history of use for VTE treatment, and patient preference for oral warfarin vs. injectable LMWH.

The American College of Chest Physicians, American Society of Clinical Oncology and the National Comprehensive Cancer Network clinical guidelines currently recommend LMWH treatment for cancer-related VTE. The study was funded by the National Cancer Institute and led by Kaiser Permanente Colorado.