The Optimal Duration of Anticoagulant Therapy In Patients with Cancer-Related Deep Vein Thrombosis: The Advantage of Using Residual Vein Thrombosis (the Cancer-DACUS Study)

Abstract 190 Type and duration of anticoagulation is still matter of debate in cancer patients with acute Deep Vein Thrombosis (DVT) of the lower limbs. Residual Vein Thrombosis (RVT) has been proven to be effective for assessing the optimal duration of oral anticoagulants in non cancer patients (Siragusa S et al Blood 2008:112:511-5). In the present study we evaluate the role of a RVT-based management of anticoagulation with Low-Molecular Weight Heparin in cancer patients with acute DVT. Materials and Methods. Patients with active cancer and a first episode of DVT were treated with LMWH for 6 months (the first month at full dosage followed by dose reduction of 25% in the next 5 months). At the end of treatment, they were managed according to RVT findings: those with RVT were randomized to continue anticoagulants for 6 additional months (Group A1) or to stop it (Group A2), while patients without RVT stopped LMWH (Group B). Outcomes were recurrent venous thromboembolism and/or major bleeding; patients were followed up for one year after LMWH discontinuation. Results. Over a period of 36 months, 409 patients were evaluated; 62 were excluded (refusal, need for continuing anticoagulation, etc). In total, 347 were included in the study (Table 1). RVT was detected in 242 (69.7%) patients; recurrent events occurred in 21.9% of those randomized to discontinue and 14.2% of those who continued LMWH. In patients without RVT (105, 30.3%), recurrent events occurred in 3 cases (2.8%) (Table 2 and Figure 1). The adjusted Hazard Ratio (HR) for age and sex between RVT groups (Group A2 vs A1) was 1.58 (95% confidence interval [CI], 0.85–2.93; P=.145). The adjusted HR between group A1 versus RVT-negative group (B) was 4.54 (CI 2.3–6.66; P =.028). Five major bleeding events occurred in Group A1 and two events both in Group A2 and B (Table 2). Overall, 89 (25.6%) patients died due to cancer progression after a median follow-up of 10.2 months after heparin withdrawn. Conclusions. The Cancer DACUS is the first ever study evaluating an individual marker for assessing duration of anticoagulation in active cancer population. Final results of the study show that absence of RVT identifies a group of patients at low risk for recurrent thrombosis who can safely stop LMWH after 6 months. Disclosures: No relevant conflicts of interest to declare.