Prevention and prophylaxis of thrombosis in cancer patients

Background: Cancer Associated Thrombosis (CAT) is a significant problem in oncology that is underestimated sometimes. Venus ThomboEmbolism (VTE) is the 2nd cause of death in cancer patients. Currently, the standard of care not only for the treatment but also for the prophylaxis of CAT is the Low Molecular Weight Heparines (LMWHs). Thromboprophylaxis is an important medical decision for cancer patients in daily clinical practice. Methods: This is an observational study conducted by HeSMO in Greek Oncology units, for 1 year, aiming to record CAT management. Patients with active cancer received antithrombotic agents for thromboprophylaxis were enrolled, after signing informed consent. Results: All participating centers reported that approximately 4.300 cancer patients are managed on monthly basis, where the majority (80%) as outpatients. 426 cancer patients enrolled from 18 oncology units with mean age 65.2 years old and mean Body Mass Index (BMI) 26.10. Primary cancers were: lung 25%, pancreas 14%, stomach 8.6%, breast 8.6%, ovarian 7.7%, colorectal 7.5%, bladder 5.6% and other 22.8%. 50% of patients received LMWH at prophylactic doses while the rest received therapeutic doses [mean duration 4.42 months (SD +/- 2.68)]. 126 (30%) patients had Khorana score ≥3. 300 (70%) had Khorana score ≤2 and of these patients 68% were metastatic and 58% were receiving High Thrombotic Chemotherapy Agents (HTCA, e.g. platinum). 16 (3.8%) patients experienced VTE while 9 (56%) of them were incidental. Lower VTE risk [OR: 0.32 (95% CI 0.10, 1.0) p = 0.04] was observed in patients on therapeutic doses LMWH while higher VTE risk [OR: 3.14 (1.01, 9.9)] was observed in patients on prophylactic doses LMWH. High BMI>35 was related to significant higher risk for VTE [OR 5.37 (1.6, 18). Only six (1.4%) grade 1 bleedings were recorded in all patients who receive thromboprophylaxis. Conclusions: CAT is an important problem in oncology. Therapeutic doses of LMWH for thromboprophylaxis are effective and safe. Apart from Khorana score, some other factors such as disease stage and administration of HTCA might be taken into consideration for better CAT risk assessment in oncology patients. Legal entity responsible for the study: Hellenic Society of Medical Oncology (HeSMO), Athens, Greece. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.