Blood Clots During Chemotherapy - Awareness and Prevention

Chemotherapy, Deep Venous Thrombosis, and Pulmonary Embolism

illustration of a blood clot in a vein
Blood clots (deep vein thromboses) are common during chemotherapy. Do you know the symptoms?. Istockphoto.com/Stock Photo©wildpixel

Blood clots related to chemotherapy are talked about less than, say, nausea and vomiting, but that doesn't mean they are less of a problem. In fact, compared to the well-known symptoms of nausea, fatigue, and hair loss, they can be much more dangerous.That said, understanding the risk factors, knowing ways to lower your risk, and recognizing the symptoms, can all help you reduce your risk during cancer treatment.

Blood Clots (Venous Thrombosis or DVT) and Pulmonary Embolism

Blood clots - otherwise known in medical lingo as a "venous thrombosis”—are indeed a significant concern in people with cancer. We've known for some time that ​people with cancer in general - not just those receiving chemotherapy - have an increased risk of blood clots. On their own, blood clots in the legs can be painful, but the greatest concern is that these clots will break off and travel to the lungs. When this occurs - something referred to as pulmonary embolism - it is a medical emergency.

If you travel internationally, you may be familiar with the pre-flight videos which tout the importance of leg exercises to prevent blood clots, but we seldom hear of this risk with otherwise predisposing activities - such as going through chemotherapy. In this case, what you haven't heard may hurt you. In fact, this is one aspect through which being your own advocate in your cancer care - learning about this potential complication, and contacting your doctor if you are concerned - can really make a difference in your well-being and possibly even your outcome.

Risk of Blood Clots During Chemotherapy

It's always been suspected that people going through chemotherapy have an increased risk of blood clots, but it wasn't until 2013 that this aspect of cancer treatment was evaluated alone. In a large study, it was found that the incidence of blood clots going to chemotherapy was 12.6 percent, compared to a risk of 1.4 percent for cancer patients not receiving chemotherapy.

 

The risk was higher in some cancers than others, with cancers such as pancreatic cancer and lung cancer having greater risk. In addition, some chemotherapy drugs and medications used to counteract the side effects of chemotherapy were also associated with an increased risk. In this study, drugs which increased risk included Platinol (cisplatin), Avastin (bevacizumab), and Epogen or Procrit (the red blood stimulator erythropoietin.)

Other Risk Factors for Blood Clots During Cancer Treatment

In addition to chemotherapy, what other treatments and conditions may raise the risk of blood clots for people living with cancer? Some risk factors include:

  • Surgery - In some studies, the risk of blood clots in cancer patients has been up to 50 percent after surgery
  • Hospitalization, especially stays exceeding one day
  • Prolonged bed rest
  • Central venous access (such as having a chemotherapy port)
  • Medications called angiogenesis inhibitors (such as Avastin)

Symptoms of Blood Clots

In order to be aware of possible symptoms, it can help to break these down into symptoms usually seen with a blood clot in the legs (venous thrombosis) and symptoms related to a blood clot which has broken off and traveled to the lungs (pulmonary embolism.)

Symptoms of venous thrombosis (blood clots in the leg) include symptoms in the calves or upper leg including:

  • Redness
  • Tenderness
  • Swelling
  • Warmth

Symptoms due to pulmonary embolism may include:

  • Sudden chest pain - often a sharp pain. Keep in mind that sometimes clots travel to different areas in the lungs, and pain may not be in just one location
  • Shortness of breath
  • Coughing or coughing up blood
  • Lightheadedness
  • Unconsciousness
  • Cyanosis - a blue discoloration of the skin and lips
  • Heart arrhythmias - abnormal heart rhythms
  • Elevated respiratory rate and heart rate with a low blood pressure

Medication Prevention of Blood Clots During Chemotherapy

Medications—anticoagulants—are being used more frequently in recent years to reduce the risk of blood clots in cancer patients. This is referred to a "prophylactic anticoagulation" which, translated, means preventive blood-thinning.  

There are several medications physicians may recommend prophylactically. Recent studies suggest that medications such as heparin work better in people with cancer than medications that interfere with vitamin K—such as Coumadin (warfarin), but different medications may be recommended depending on your particular situation. Some of these drugs (which you may hear referred to as low molecular weight heparin) include:

  • Lovenox (enoxaparin)
  • Fragmin (dalteparin)
  • Innohep (tinzaparin)
  • Arixtra (fondaparinux) - this is a newer "heparin-like" drug

What Can You Do Yourself to Lower Your Risk of Blood Clots During Chemo?

In medicine, we tend to talk about drugs when it comes to prevention, yet there are many things you can do yourself to reduce your risk. The first and most important step is simply to educate yourself and ask questions. Become familiar with the symptoms of blood clots and pulmonary embolism. If you are concerned at all, don't wait, but contact your doctor immediately. Ask your oncologist if there is anything special you can do to reduce your risk, or if she would recommend a medication to lower risk.  In addition, you may wish to:

  • Move around as much as possible, within your limits. If you are not sure how much activity is recommended, ask your doctor. Frequent short periods of physical activity are better than infrequent longer activities 
  • Even if you are bed-ridden, exercise your legs. Your doctor or nurse can help demonstrate these exercises for you. You can try pointing your toes toward your head and then the floor several times (again, talk to your doctor as the best measures may vary depending on your particular medical situation)
  • Avoid long drives.  If you must be in the car for an extended period of time, schedule frequent stops—at least every hour—and get out of the car and walk around
  • In addition to other precautions for flying with cancer, try to get up at least every hour, and preferably every 30 minutes and move around. You can do leg exercises even when seated.  Depending on your situation, your oncologist may consider treating you with an anticoagulant (for example, low molecular weight heparin) prior to your flight. Make sure to ask. DVT's due to plane travel are common enough that they've been coined economy class syndrome
  • Don't smoke
  • If your doctor recommends compression stockings, make sure to follow her directions
  • Avoid crossing your legs
  • Avoid tight fitting clothing, especially clothing that is tight around your knees or in your groin area
  • Elevate your legs when possible
  • Avoid caffeine and alcohol.  Both caffeine and alcohol can lead to dehydration, and dehydration raises the risk of blood clots

Sources:

American Society of Clinical Oncology. Cancer.Net Preventing and Treating Blood Clots. Updated 01/20/15. http://www.cancer.net/research-and-advocacy/asco-care-and-treatment-recommendations-patients/preventing-and-treating-blood-clots

Garcia Escobar, I., Antonio Rebollo, M., Garcia Adrian, S. et al. Safety and efficacy of primary thromboprophylaxis in cancer patients. Clinical and Translational Oncology. 2016 May 4. (Epub ahead of print).

Khorana, A., Dalal, M., Lin, J., and G. Connolly. Incidence and predictors of venous thromboembolism (VTE) among ambulatory high-risk cancer patients undergoing chemotherapy in the United States. Cancer. 2013. 119(3):648-55.

Posch, F., Konigsbrugge, O., Zielinski, C., Pabinger, I., and C. Ay. Treatment of venous thromboembolism in patients with cancer: A network meta-analysis comparing efficacy and safety of anticoagulants. Thrombosis Research. 2015. 136(3):582-9.

Vitale, C., D’Amato, <., Calabro, P. et al. Venous thromboembolism and lung cancer: a review. Multidisciplinary Respiratory Medicine. 2015. 10(1):28.

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