“Real-world” recurrence rate of cancer-associated-VTE treated with Low Molecular Weight Heparin Therapy: The Mayo Clinic Experience.

Abstract

e17687 Background: Patients with cancer associated VTE have a 4-fold higher risk of mortality compared to cancer patients with no VTE. If anticoagulants are discontinued, patients with cancer associated VTE have 30% recurrence rates at one year . In controlled clinical trials, low molecular weight heparin (LMWH) reduced cancer associated VTE recurrence compared to vitamin K antagonists (VKA) by nearly 50%. VTE recurrence rates in a “real world” setting are unknown Methods: Using a retrospective study design, consecutive Mayo Clinic patients with pancreatic, breast, and lung cancer associated VTE treated solely with weight-based LMWH were assessed from Jan 1st 2012-Dec 31st2013. Patients were analyzed by clinical presentation of VTE, LMWH dose, major bleeding and objectively confirmed VTE recurrence. Patients were followed until death or until their last oncologic follow up. Results: 103 patients with breast cancer (40.8%; n = 42), pancreatic cancer (31.1%; n = 33), or lung cancer (27.2%; n = 28) were followed for a mean 597 days (range: 21-9756 days). Of these, 73.8 % had stage IV disease. Just over half received once daily ( 57.2 %) compared to twice-daily LMWH (40.7%). Over the study period, 17/103 (16.5%) patients experienced an objectively defined VTE recurrence. Of these, most occurred while on therapeutic LMWH (15/17). Recurrence rates were numerically more than twice as frequent for pancreatic cancer (25.8%) compared to breast cancer (11.3%) or lung cancer (14.2%). Of 17 recurrences, 6 were PE, while 11 had DVT (p = 0.001). The recurrence rate for patients on QD LMWH dosing was 13.5% (8/59) vs. 21.4% (9/42) for patients with BID LMWH dosing. On binary logistic regression, recurrence was not influenced by LMWH dosing frequency (once daily vs. twice daily), sex, active chemotherapy, cancer type, cancer stage, and biomarkers, including creatinine, WBC, and platelets. Conclusions: Real world cancer associated VTE recurrence rates are high at 16.5% (17/103) and comparable to published RCT data. There were no significant predictors for VTE recurrence.