Evaluation of Fibrin Structure Marker in Cancer Patients Treated and Not Treated With LMWH

Rationale. Venous thromboembolism (VTE) is a major complication often encountered in oncology and onco-hematology, and difficult to handle. It involves the activation of coagulation with the generation of fibrin and plasmin and angiogenesis activation. Low molecular weight heparins (LMWH) are used to treat cancer associated thrombosis. Furthermore, they could have an inhibitory effect on tumor progression.

International recommendations on the treatment and prophylaxis of the disease allow a better management of VTE in patients with cancer. Its prevalence is high, occurring in 15-20% of the patients. It remains the second leading cause of death after cancer. LMWH at therapeutic dosage for at least three months and preferably six months without oral bridging is the reference treatment for VTE, which showed a 50% reduction in the risk of recurrent thromboembolism without increasing the hemorrhagic risk. In case of VTE recurrence under LMWH treatment, the dose can be increased by 10%. Preliminary results suggest that the fibrin structure marker would predict the hemorrhagic or thromboembolic risk, and show that LMWH has a dose-dependent effect on fibrin structure. This marker is evaluated as a tool to guide the treatment of VTE by LMWH in patients with cancer.

Main objective. To assess the fibrin structure marker in the plasma of cancer patients, treated or not treated with LMWH at prophylactic doses at enrollment or therapeutic doses, to determine the venous thromboembolic risk. The occurrence of thromboembolic events in patients without treatment or of recurrent thromboembolic events in patients under LMWH treatment will be studied, depending on the location and type of cancer, metastases, and treatment of cancer.

Patients. At least 300 adult patients over 18 years with all types of malignancies documented before or during therapeutic treatment with LMWH for thromboembolic event. They will be monitored every month in consultation or during hospitalization in the Internal Medicine Department. The patients under prophylaxis with LMWH at enrollment will also be included and classified in the group of prophylactic patients. The patients who receive prophylactic treatment during will be included and classified in the group of untreated patients.

Will not be included: patients with sepsis, severe infections, pneumonia, surgery, suspected thromboembolic event related to catheter implantation, vitamin K antagonists (VKA) in progress, and those with impossible follow-up.