Tinzaparin and VKA use in patients with cancer associated venous thromboembolism: A retrospective cohort study

• Six months of treatment for VTE in patients with cancer are needed.
• Be careful of a « provoked » first event (after surgery).
• The recurrent rate was mainly higher during the six first months.
• When anticoagulation was stopped before sixth month, the risk was eight fold higher.
• After six months: no impact of the type of anticoagulation on the recurrent rate.

IntroductionAfter 6 months, little is known about the optimal anticoagulant strategy for an acute episode of VTE in cancer patients.Aims, objectives and methodsThe objective was to determine the risk of recurrent VTE and anticoagulant-related bleeding at 6 months of follow-up and after 6 months, in cancer patients who received tinzaparin during at least 3 months for an acute episode of VTE. We conducted a multicenter retrospective cohort study from January 2004 to March 2011.ResultsTwo hundred fifty patients were included. Stopping anticoagulation before 6 months in patients considered at low risk by physicians (i.e.; patients who had prior cancer surgery) and for another reason than bleeding or death was the only factor associated with a significant increased risk of recurrent VTE (OR 7.2 95%CI, 2.0-25.7; p = 0.002). The type of anticoagulation did not influence the risk of recurrent VTE. We found a trend towards an increased risk of recurrent VTE when anticoagulation was stopped because of major bleeding while on anticoagulant therapy and patients with metastatic cancer (OR 2.3, 95%CI, 0.9-5.4; p = 0.07; and OR 1.8 95%CI, 1.0-3.3; p = 0.07; respectively). No factors were found to increase the risk of major bleeding at 6 months and after. The overall mortality was 42.8%.ConclusionsThe risk of recurrent VTE was mainly related to early discontinuation of anticoagulation in patients considered at low risk of recurrence (after surgery). When the anticoagulation was stopped before the sixth month, the risk was eight fold higher. After 6 month, the risks of recurrent VTE, major bleeding and death were similar in patients with either VKA or tinzaparin when patients were treated according to the guidelines.