Effects of tinzaparin on the presence of residual thrombus in patients with cancer-associated thrombosis

<bold>Introduction:</bold> Residual thrombosis (RT) assessed by computed tomography (CT) in patients with venous thromboembolism (VTE) was reported to be 23% (C. Becattini et al. JTH 2019). However, information on RT is scarce in patients with cancer-associated thrombosis (CAT). The objectives of this study were to assess the presence or absence of RT and to identify variables associated with RT. <bold>Methods:</bold> Consecutive cohort of CAT patients from January 2008 to June 2022. During their neoplasm follow-up, all patients underwent follow-up CT, and the presence of RT was evaluated. Within VTE, we included patients with deep vein thrombosis (DVT), pulmonary embolism (PE), and unusual thrombosis locations. <bold>Results:</bold> The study included 511 CAT patients treated with tinzaparin who underwent at least one follow-up CT. The mean age was 63.1 +/- 13.2 years, with a slight male predominance (52%). Regarding VTE location: PE (38.4%), DVT (35.6%), DVT and PE (16.4%), and atypical VTE (9.6%). During a median follow-up of 17.6 months (p25-75: 7.9-34) and a median anticoagulation duration of 5.7 months (p25-75: 3.1-12.9), 35.8% of patients (n=183) had RT. Neoplasms most associated with RT were pancreas (57.7%), gastric (57.1%), and gynaecologic (54.3%). In the logistic regression analysis, variables associated with RT were ECOG performance status (OR 1.99, 95% CI 1.05-3.77), metastases (OR 1.87, 95% CI 1.24-2.81), lower limb DVT (OR 2.05, 95% CI 1.33-3.16), and incidental VTE (OR 0.56, 95% CI 0.36-0.87). <bold>Conclusion:</bold> One-third of cancer-associated VTE patients have residual thrombosis, with identified variables associated with residual thrombosis.