Clinical outcomes of cancer-associated isolated distal deep vein thrombosis: a comparison between asymptomatic and symptomatic thrombosis—findings from the ONCO DVT Study

Abstract

Background: The risk of recurrent venous thromboembolism (VTE) in patients with isolated distal deep vein thrombosis (IDDVT) is generally low, particularly when IDDVT is asymptomatic. However, cancer patients with IDDVT, even asymptomatic IDDVT, may be at a higher risk of recurrent VTE. Objectives: To compare the clinical outcomes of cancer patients with asymptomatic and symptomatic IDDVT. Methods: The ONCO DVT trial is a randomized clinical trial that compared 12-month versus 3-month edoxaban treatment regimens in cancer patients with IDDVT. In this post hoc analysis, 601 patients were categorized into the asymptomatic (n = 479) and symptomatic (n = 122) groups based on IDDVT-related symptoms at diagnosis. The primary outcome was the composite of symptomatic recurrent VTE or VTE-related death at 12 months, while the major secondary outcome was major bleeding at 12 months. Results: The cumulative 12-month incidence of the primary outcome was lower in the asymptomatic group than that in the symptomatic group (2.9% vs 13.4%; P < .001; hazard ratio, 0.21; 95% CI, 0.10-0.47). Among the 12 patients with symptomatic recurrent VTE in the asymptomatic group, 8 (67%) had recurrent IDDVT, and 11 (92%) experienced recurrence after discontinuing anticoagulation therapy. The cumulative 12-month incidence of major bleeding was lower in the asymptomatic group than that in the symptomatic group (7.8% and 13.2%; P = .048). Conclusion: The risk of recurrent symptomatic VTE was lower in cancer patients with asymptomatic IDDVT than in those with symptomatic IDDVT. Most recurrent VTE events were recurrent IDDVT, with the majority occurring after discontinuing anticoagulation therapy.