Assessment of patient characteristics in cancer-associated venous thrombosis in Türkiye (CAT-TR study)

Aim: In cancer patients, the overall risk of venous thromboembolism (VTE) is increased 7-fold, and in cases of certain malignancies, this risk increases to 28-fold. The main objectives of this study are to describe patterns of use of anticoagulants for the treatment of cancer-related VTE in Türkiye and to assess patient characteristics. Material and Methods: This was a multicenter, retrospective, descriptive study utilizing data from 17 centers across Türkiye. We included 2936 patients with a diagnosis of any cancer and a diagnosis of proximal lower-limb deep vein thrombosis (DVT) and/or pulmonary embolism (PE) between January 1, 2016, and December 31, 2019. These patients were only included if the cancer diagnosis was made at least 6 months before the diagnosis of VTE or within 30 days following the diagnosis of VTE. Patients were followed from the day after the index date until the earliest date among the dates of death, the end of the study, or the end of the 6-month treatment period. Results: The study included 2796 patients with VTE between 2016 and 2019. While 41.4% of the participants were female, 58.6% were male, and 66.1% of the patients had DVT while 45.2% had PE. Furthermore, 52.7% had a history of smoking and only three patients had known hereditary thrombophilia. Lung cancer was the most common type of cancer, diagnosed in 872 patients (29.3%), followed by colon cancer diagnosed in 255 patients (8.6%) and breast cancer diagnosed in 202 patients (6.8%). Among these patients, 70.3% were in an advanced stage of the disease. Chemotherapy was administered to 469 (65.7%) patients at the time of disease onset. Among the patients with VTE, 99.5% were treated, and low-molecular-weight heparin was used in 97.5% of these cases while 3% of the patients were treated with direct oral anticoagulants. Bleeding was observed in 1.6% of the patients who participated in this study, and 39.1% of the bleeding events whose type was specified were categorized as major bleeding. Bleeding was most intense in the gastrointestinal tract (56.7%). Recurrence was observed in 1.5% of the patients and improvement was observed in 42.1%. In the first 6 months after diagnosis, 14.3% of the patients died. Causes of mortality could not be obtained from the patients’ records. Conclusion: VTE is common in patients with active cancer and associated with high recurrence and mortality rates. Efforts are needed to prevent VTE, diagnose it in time, and reduce the recurrence rates, especially in the first year after VTE diagnosis.