Clinical course of isolated distal deep vein thrombosis in patients with active cancer: a large multicenter cohort study

F. Dentali1, S. Pegoraro1, S. Barco2, M. di Minno2, D. Mastroiacovo3, F. Pomero4, C. Lodigiani5, F. Bagna6, W. Ageno1, M. di Nisio7 (1Varese, Italy, 2Mainz, Germany, 3Naples, Italy, 4Avezzano, Italy, 5Cuneo, Italy, 6Rozzano-Milano, Italy, 7Chieti, Italy)

Date: 16.02.2017,
Time: 11:00 - 12:00

Objective: Although isolated distal deep vein thrombosis (IDDVT) is frequently associated with cancer, no study has specifically evaluated the long-term clinical course of IDDVT in active cancer patients. The aim of this study is to provide data on the rate of recurrent venous thromboembolism, major bleeding events and death in IDDVT patients with active cancer.

Methods: Consecutive patients with active cancer and an objective diagnosis of IDDVT (January 2011-September 2014) were retrospectively included. We collected Information on baseline characteristics, IDDVT location and extension, venous thromboembolism risk factors, type and duration of anticoagulant treatment. The primary study outcome was the composite of objectively documented recurrent venous thromboembolism events. The primary safety outcome was major bleeding. All patients underwent regular follow-up visits or telephone contacts every six months up to 24 months after IDDVT diagnosis.

Results: 308 patients (mean age 66.2±13.2 years, females 57.1%) with solid (n=261) or hematologic (n=47) cancer were included in 13 centers. Cancer was metastatic in 148 (48.1%) patients. All but three patients (99.0%) received anticoagulant therapy which consisted of low molecular-weight heparin in 288 (93.5%) patients, fondaparinux in 15 (4.9%), and unfractionated heparin in 1. Vitamin K antagonists were used for the long-term treatment in 46 patients (14.9%) whereas all others continued the initial parenteral agent for a mean treatment duration of 4.2 months (±4.6 months). During a total follow-up of 355.8 patients-year (mean 13.9 months), there were 47 recurrent objectively-diagnosed venous thromboembolism for an incidence rate of 13.2 events per 100 patients year. Seven (2.3%) patients had a major bleeding event and 138 (44.8%) died.

Conclusion: Cancer patients with IDDVT have a high risk of venous thromboembolism recurrence. Additional studies are warranted to investigate the optimal intensity and duration of anticoagulant treatment for these patients.