Anti Xa Activity in Cancer Patients Receiving Low-molecular-weight Heparin for Venous Thromboembolism

Inclusion Criteria:

Case:

* Being affiliated to a social security scheme
* Having an active solid or hematological cancer (myeloma or lymphoma), histologically or cytologically confirmed, for which the active state will be defined by the existence of a tumoral active disease or an incomplete tumoral resection or the persistence of high tumor markers after complete resection of the tumor.
* The venous thromboembolism disease has to be:
* A deep vein thrombosis of lower extremity (proximal or distal) confirmed by the lack of compressibility of a venous segment under the ultrasound probe or the presence of a venous gap in CT venography or phlebography;
* or a thrombosis of the vena cava or the iliac vein confirmed by an abdominal CT scan with contrast or a venous ultrasound or an ilio-cavography;
* or a pulmonary embolism confirmed according to the guidelines of the European Society of Cardiology : through a gap in a pulmonary artery, at least segmental or multiple gaps sub-segmental on spiral CT angiography of the pulmonary arteries or by a high appearance probability on a lung radionuclide imaging, or by clinical symptoms of pulmonary embolism accompanying symptomatic proximal vein thrombosis confirmed by a venous ultrasound or by an unexplained echocardiography acute pulmonary heart in presence of a high clinical probability and for patients who are unfit for transport and with cardiogenic shock
* The venous thromboembolism disease can be asymptomatic or incidentally discovered but is confirmed objectively.
* No cons-indication to low molecular weight heparin treatment at therapeutic dose.
* Prescription in the last 72 hours of a low molecular weight heparin treatment or fondaparinux at therapeutic dose.

Control:

* Being affiliated to a social security scheme.
* Being free from malignant tumor pathology detectable at the time of inclusion.
* Being afflicted with venous thromboembolism defined by the same criteria of cancer subjects.
* The venous thromboembolism disease can be asymptomatic or incidentally discovered but is confirmed objectively.
* No cons-indication to low molecular weight heparin treatment at therapeutic dose.
* Prescription in the last 72 hours of a low molecular weight heparin treatment or fondaparinux at therapeutic dose.

Exclusion Criteria:

Case:

* Visceral vein thrombosis of the upper limb or venous thrombosis of the superior vena cava system because their scalability under treatment, including the risk of embolic recurrence is less known that pulmonary embolism and thrombosis of the lower limbs and their diagnostic modalities are less formalized.
* Tumor disease not confirmed histologically or cytologically.
* Follow-up after complete tumor resection without elevated tumor markers.
* Cons-indication to low molecular weight heparin treatment at therapeutic dose.
* Initial treatment with another anticoagulant molecule than LMWH or fondaparinux (thrombin inhibitor, direct factor Xa inhibitors)
* Severe renal impairment defined by a creatinine clearance below than 30 ml / min at baseline.
* Known pregnancy or lack of effective contraception for women of childbearing age or breastfeeding.
* Patient previously included in the study.
* Impossible follow-up.
* Life expectancy less than 6 months.
* Patient whose weight is greater than 100 Kg.

Control:

* Not yet confirmed suspected malignant tumor pathology associated with the venous thromboembolism disease.
* Active cancer in the last 2 years.
* Cons-indication to low molecular weight heparin treatment at therapeutic dose.
* Initial treatment with another anticoagulant molecule than LMWH or fondaparinux (thrombin inhibitor, direct factor Xa inhibitors)
* Severe renal impairment defined by a creatinine clearance below than 30 ml / min at baseline.