Analysis of Pro-coagulant and Thrombin-generation Markers for the Prediction of Therapeutic Failure in Cancer Patients at Risk for Recurrence of Venous Thromboembolism: A Pilot Study
Therapeutic failure in cancer patients at high risk for recurrence of Venous thromboembolism
(VTE) may be as high as 20% and the risk of death from a recurrent episode of pulmonary
embolism is at least 8%. Studies that have used pro-coagulant and thrombin generation
markers support the notion that cancer is associated with a hypercoagulability state and
that intensified doses of anticoagulation may be necessary to suppress this state. Thus, it
may be possible that by using these tests, we would identify the patients that do not
respond to standard doses of anticoagulation. To date, only few small studies have evaluated
the use of pro-coagulant markers in cancer patients but this data is promising. Our study
will measure pro-coagulant markers in cancer patients at risk for VTE recurrence to
determine if there is a relationship between the changes in the levels of pro-coagulant
markers and VTE recurrence while taking anticoagulation with low-molecular weight-heparin
(LMWH). The evaluation of the pro-coagulant markers may enable new treatment strategies in
cancer patients who fail their initial treatment. Patients will be stratified by a risk
model developed by our group and will be validate with this study. This new approach has the
potential to improve the recovery of patients, to reduce death and disability due to clots
in the veins of legs or arms and/or lungs.
Observational Model: Cohort, Time Perspective: Prospective
Relative changes on biochemical markers
On each blood sample the following pro-coagulant and thrombin-generation markers will be measured: Prothrombin fragments F1+2; D-dimer, Activated Protein C thrombin Activation Potential (ThromboPath test), thrombin-antithrombin (TAT) Soluble P-selectin. Tissue Factor antigen. For each patient, we will calculate baseline values and the relative changes (delta) of procoagulant and thrombin generation markers. The relative changes (delta) will be defined by the percentage of change in the marker at each visit relative to baseline measurement.
at initiation of anticoagulation (baseline); at 7 +/- 2 days; 28 +/- 2 days; 35 +/- 2 days; 90 +/- 2 days; and 180 +/- 2 days after initiation of anticoagulation.
Philip S Wells, MD
Ottawa Hospital Research Institute
Canada: Ethics Review Committee