Prevention of venous thromboembolism in ambulatory patients with active cancer: Results from ACT4CAT study

e18677 Background: Venous ThromboEmbolism (VTE), might be a challenge with a lot of negative consequences for patients with active cancer. VTE affects ongoing anticancer treatment, worsening morbidity and mortality, increases economic burden and escalates psychological distress. Incidence of VTE in patients with cancer reported 20%. Current guidelines recommend pharmacologic prophylaxis in ambulatory cancer patients with Khorana score ≥2. Methods: ACT4CAT is a prospective observational phase IV study conducted by HeSMO Greece, aiming to record the clinical practice of VTE prophylaxis in active cancer patients. Ambulatory patients who received thromboprophylaxis enrolled after signing informed consent. Study was approved by bioethics committee. Results: 691 patients from 19 oncology departments received thromboprophylaxis in 1st line 57.6%, 2nd line 14.8%, adjuvant 9.0% and neoadjuvant 7.5%. Age ≥65 found 55%, BMI≥30 17.5% and males 63%. Tumor types: gastrointestinal 45.4%, lung 25.8%, urological 11.6%, gynecological 6.0%, breast 4.2% and others 7.0%. High-Risk for Thrombosis Agents (HRTAs) received 87.2%, specifically: platinum agents (56.3%), antimetabolites (54.2%) and immunotherapy (12.1%). 54,5% of the anticancer agents had potential drug-drug interaction (DDI) with anticoagulation treatment. Thromboprophylaxis duration lasted 5.3±3.5 months. Main agents were: tinzaparin 89.6%, fondaparinux 6.0%, bemiparin 2.2%, enoxaparin 1.6%, apixaban 0.3% and rivaroxaban 0.3%. Intermediate thromboprophylaxis dose received 68% of patients, lower in adjuvant setting (45.2%), with a preference in metastatic cases (OR: 1.5 95% CI: 1.02-2.3, p = 0.026). 14 thrombotic events reported (efficacy: 98.0%, 95%CI: 96.6-98.8%) and 12 grade 1 bleeding (1.7%, 95%CI: 1.0-3.0%). Conclusions: Prevention of VTE in ambulatory patients with active cancer found effective and safe. Apart from the Khorana score, specific patient characteristics, metastasis, HRTAs and DDIs seemed that affect clinical decision for thromboprophylaxis mainly with LMWHs and often on intermediate dose regardless the clinical setting. Oncologists appeared informed that CAT is not negligible risk. Clinical trial information: NCT03909399. [Table: see text]