Chemotherapy may stimulate the release of tiny bubbles from the surface of cancer cells that can cause potentially fatal blood clots, a new study has found.
Most deaths from cancer are caused by uncontrolled growth of the tumour in vital organs. However, the second most common way that cancer kills is by triggering blood clotting resulting in thrombosis, such as pulmonary embolisms.
This causes blockage of major blood vessels – preventing oxygen and nutrients from reaching vital organs. Though often life-saving and life-prolonging, chemotherapy is associated with a six to seven-fold increase in the risk of
thrombosis in cancer patients.
The link between cancer and thrombosis was noted over 100 years ago, but the reasons for the association have been
Researchers from University of Otago in New Zealand discovered that cancer cells treated with chemotherapy release
lipid-rich bubbles from their membranes that activate coagulation (clotting) processes. “We now have insight into how these bubbles from dying cancer cells may cause thrombosis during chemotherapy,” said Alex McLellan, associate professor at University of Otago.
Researchers have demonstrated that certain solid cancers are more active in promoting blood coagulation, as compared to lymphomas. “A general pattern is that cancers such as pancreatic, lung and brain cancers carry the largest risk of thrombotic events,” said McLellan.
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The group analysed the contribution of individual coagulation factors to the risk. Although they identified the coagulation factor known as Factor V on the cancer bubbles, it was not essential for the rapid clotting induced by the bubbles.
Instead an over-abundance of clotting lipids and a molecule called Tissue Factor on the cancer bubbles were
responsible. “While chemotherapy can be lifesaving, it does carry some risks. A new challenge is being able to identify those patients most at risk and providing effective management to mitigate this risk,” said McLellan.
The study was published in the journals Biochimica et Biophysica Acta and Oncotarget.