Extended anticoagulation with DOACs in patients affected by hematologic malignancies and venous thromboembolism: a monocentric experience

The management of cancer-associated thrombosis (CAT) in hematologic malignancies is particularly challenging due to the high competing risks of recurrence and bleeding. While international guidelines recommend extended anticoagulation for patients with active cancer, the optimal dose intensity beyond the initial six months remains uncertain. We retrospectively evaluated a risk-adapted strategy using vein recanalization to guide direct oral anticoagulant (DOAC) dosing in a monocentric cohort of 148 onco-hematologic patients. During the extended phase, patients with persistent thrombosis remained on full-dose DOACs, while those with vein recanalization and active cancer were switched to low-dose DOACs. Over a median extended treatment follow-up of 35.3 months, the incidence rate of bleeding adverse events was 9.9 per 100 patient-years for full-dose therapy compared to 0.8 for low-dose therapy. Specifically, clinically relevant non-major bleeding rates were 9.2 vs. 0.4 per 100 patient-years, respectively. Recurrent VTE incidence was 4.3 per 100 patient-years in the full-dose group and 1.3 in the low-dose group. Our findings could suggest that a “low dose fits all” approach may be inappropriate for this high-risk population. Onco-hematologic patients with persistent venous thrombosis may benefit from continued full-dose anticoagulation, while dose de-escalation appears safe and effective once recanalization occurs. These results should be interpreted with caution given the retrospective, single-center design and small sample size.