What is a blood clot?
Blood clotting is a normal and healthy physiological process to stop bleeding when an injury has occurred. When blood clots happen within a vessel that has not been damaged, they can be problematic. The medical term for this type of problematic blood clot in vein is a deep venous thrombosis (DVT). Damage to or inflammation of a blood vessel increases the risk of a blood clot forming. A foreign body in a blood vessel also increases the risk. A common place for them to start is in the calves of the legs. They can also form around central lines such as PICC lines, Hickman lines, or Port-a-caths.
Blood clots are dangerous when they are in the deep venous system. A complication of a DVT is when the clot travels to the lung, which is called a pulmonary embolism. The clot can lodge in the small vessels of the lung and block blood flow. This is a life threatening condition.
Risk factors for blood clots:
Cancer
Inherited blood clotting disorder
Bed rest (such as a prolonged hospital stay)
Surgery - increased risk from the injury of surgery itself as well as prolonged bed rest
Being overweight/obesity - increases the pressure on your veins
Pregnancy - increased pressure on veins
Birth control pills or hormone replacement - increases the coagulability (ability to clot) of blood
Smoking - affects blood clotting and circulation
Sitting for long periods of time (such as car or plane travel)
Why does cancer increase the risk of blood clots?
There is clear evidence that there is a link between cancer and blood clots. There are several explanations for this link:
Cancer itself may increase the incidence of blood clots: cancer and/or tumors may release chemicals that trigger clotting
Mass effect from a tumor: depending upon the location of a solid tumor, if near a vessel the tumor itself could press against the blood vessel, causing damage or inflammation and increase the risk of a blood clot forming.
Treatment for cancer: many drugs that are used to treat cancer also increase the activation of clotting factors which leads to an increased incidence of blood clots.
Radiation: radiation can damage a blood vessel, causing inflammation and damage which increases the risk of a blood clot
If an individual already has an established risk factor for blood clots (listed above), cancer adds to the risk, increasing it even further.
Symptoms of a blood clot
Potential symptoms of a blood clot:
Leg pain, especially in the calf
Redness or swelling of one leg, may or may not be associated with pain
Pain at the site of your port or central line
Chest pain
Shortness of breath
Feel like your heart is racing (fast pulse)
A cough without other symptoms of illness
Coughing up blood
How is a blood clot diagnosed?
This depends upon where the blood clot is located. Most blood clots are diagnosed with an ultrasound. A CT scan may also be necessary to look for a blood clot in the lungs.
Potential treatments for a blood clot
Most blood clots are treated with blood thinners (also called anticoagulants). These can be injectable or oral medications. There are many options for oral medications now including coumadin (which needs to be monitored with regular blood tests) and a new class of blood thinners that do not require monitoring. Your oncologist would make recommendations about which one is best to use in your individual case.
Can you prevent a blood clot?
Unfortunately some risk factors are not under our control but there are some areas where you could reduce your risk. Take control where you can and work on the following recommendations to reduce your risk of blood clots.
Try not to sit or stand for more than one hour at a time, get up and move to keep the blood in your legs circulating.
Long travel has been associated with increased incidence of blood clots in the legs. During long travel in the car or on a plane, make sure to get up every hour to move your legs.
Wear compression stockings if prescribed. This helps the blood to keep circulating
Exercise - there is a theme here, moving your body helps decrease the incidence of clot
Lifestyle changes - if overweight, losing weight can help decrease your risk
Smoking cessation - smoking increases the risk of blood clots