Patient characteristics and long-term outcomes beyond the first 6 months after a diagnosis of cancer-associated venous thromboembolism

Introduction: Little is known about the clinical course and treatment decisions in patients with cancer-associated venous thromboembolism (VTE) beyond the initial treatment period of 3 to 6 months. This information is important for clinicians and patients to inform their decisions regarding duration of anticoagulation.

Materials and methods: We reviewed health records from consecutive patients referred to our institution for cancer-associated VTE management between 2013 and 2015 to describe their clinical course and outcomes from 6 to 24 months following their index VTE. Details on patient and cancer characteristics, objectively documented recurrent venous thromboembolism (rVTE), clinically relevant bleeding (CRB) and overall mortality were captured.

Results: 524 patients met eligibility criteria and 322 were alive at 6 months after the index VTE. At 6 months, anticoagulation was continued in 222 patients (68.9%). During follow-up, there were 33 rVTE events in 30 patients (1-year cumulative incidence of 8.2%; 95% CI: 5.5%-11.6%), and 16 CRB events in 15 patients (1-year cumulative incidence of 4.1%; 95% CI: 2.3%-6.7%); 20 (60.6%) rVTE events and 13 (81.3%) CRB events occurred while on anticoagulation. One-year survival beyond 6 months was 73.7% (95% CI: 68.5%-78.2%). A higher proportion of patients with advanced cancer and receiving cancer treatment was found among those who continued anticoagulation beyond 6 months compared to those who stopped anticoagulation.

Conclusions: Patients with cancer-associated VTE who are alive at 6 months after VTE diagnosis remain at high risk of rVTE, CRB and death.