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    Cancer and Blood Clots: Patients Beware

    By Richard Frank, MD

     One of my patients came to my office recently and reported that he had been feeling well but noticed that one of his legs was noticeably more swollen than the other.  He has pancreatic cancer and has been receiving chemotherapy treatments with good control of the cancer. He was enjoying a good quality of life, was active and still working, and could not account for the new swelling of one of his legs.

     “Up you go to radiology,”  I said, “for a sonogram of your leg.”

    “What do you think it is?” replied the patient.

    “It’s likely to be a blood clot. A sonogram or ultrasound will make the diagnosis or rule it out.”

    I peppered him further with questions to inquire if he was having shortness of breath or chest pain with breathing. “My breathing is fine; why do you ask?” he inquired. “To see if you have any symptoms of a pulmonary embolism, or a blood clot that travels from the legs to the lung.” “OK,” he said nervously, “Now you’ve got my attention and gotten me just a little scared!” Ultimately, the sonogram of his leg did show a deep venous thrombosis and he was treated with anti-coagulation therapy.

    The point of this vignette is to alert all cancer patients that having cancer greatly increases the risks of developing blood clots in the veins of the legs, called deep venous thrombosis (DVT); abdomen; and/or in the lungs, where they are called pulmonary emboli. The medical term for these conditions is collectively referred to as venous thromboembolism (VTE).

    A VTE is a congealed mass of red blood cells, clotting proteins, and platelets (the blood element that is essential to preventing bleeding). The clot blocks the normal flow of blood past where they are formed.

    The danger with VTE is that the clot can become very large, impairing the function of a limb or ability of the lungs to transfer oxygen to the body. Numerous pulmonary emboli or a single large embolism is life- threatening.

    Why are cancer patients more at risk for the development of VTE? For several reasons, including:

    1. Some cancers secrete substances into the body that make the blood more prone to clot. This is especially true of the metastatic forms of cancer, such as advanced pancreatic or lung cancer.
    2. Chemotherapy can increase the tendency to clot (though by lowering the platelet count, these drugs can also increase the risk of bleeding).
    3. Cancer patients may be more immobile (slowing blood movement around the body) or have access devices, such as catheters for chemotherapy or PICC lines, foreign bodies that can set up a local clot.

    The classic symptoms of a leg DVT are pain, swelling, redness or unexplained cramping in the calf region. Many variations exist and some symptoms may be very mild indeed.

    Pulmonary emboli may cause shortness of breath; chest pain with breathing; an unexplained, rapid heartbeat; and/or lowering of the blood oxygen level. VTE is treated with blood thinners or anti-coagulants, such as warfarin/Coumadin, heparin, or low-molecular weight heparin (given by subcutaneous injection). Some cancer patients may require anti-coagulation therapy for the rest of their lives in order to prevent the development of new VTE.

    There are other types of blood clots and therapies, but the point of this blog is merely to alert cancer patients to the importance of being aware of VTE and reporting any suspicious new symptoms that may be consistent with a blood clot. It could save your life.


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