Introduction: Secondary prevention of venous thromboembolism (VTE) with vitamin K antagonists is often problematic in patients with cancer. We prospectively evaluated the effectiveness and safety of long-term subcutaneous dalteparin in a series of consecutive patients with symptomatic VTE and metastatic cancer.
Patients and methods: The study included 203 patients, aged 36-96 years. The initial treatment consisted of a 7-day course of subcutaneous dalteparin according to body weight. Then, patients received a fixed dose of 10 000 IU dalteparin once daily for at least 3 months. In patients developing transient thrombocytopenia the dose was reduced to 5000 IU daily while the platelet count remained <50,000; and to 2500 IU daily while it remained <10 000. Patients undergoing any surgical intervention during the study were put on 5000 IU daily during the first 4 days, switching thereafter to 10,000 IU. Patients undergoing any other invasive procedure (i.e. biopsies, punctures) received a 5000 IU dose the same day, instead of 10 000 IU.
Results: Eleven patients (5.4%) developed major bleeding complications (6 fatal) during the 3-month study period, and 18 patients (8.9%) developed VTE recurrences (2 patients died). There were no higher complication rates in patients with either liver or brain metastases, nor during thrombocytopenia, surgery or invasive procedures.
Conclusions: Fixed dose 10,000 IU subcutaneous dalteparin once daily for 3 months was not associated with more complications in patients with liver or brain metastases. The dose adjustment for patients with thrombocytopenia, surgery or invasive procedures was safe too.