Blood clots - otherwise known in medical lingo as "venous thromboembolism" - are something that has always terrified me as a physician. Maybe it was studying for boards and reviewing the answer to the question, "What is ultimately the most common cause of death?" The answer was always "pulmonary embolism" - meaning blood clots in the legs that break off and travel to the lungs.
And knowing the statistics, I remember how nervous I was when I flew while I was pregnant. Both pregnancy and flying increase the risk of blood clots. I religiously exercised my legs for what seemed to be 5 minutes every 5 minutes, and got up to walk as often as possible.
Knowing that chemotherapy increases the risk of blood clots I was equally if not more neurotic when I went through chemotherapy. I made sure to walk. I made sure to elevate my legs. I avoided crossing my leg in a ladylike fashion as much as possible. I drank plenty of fluids. But how common are blood clots after chemotherapy anyway? Was my neurotic behavior justifiable?
Researchers took a look at the incidence (a fancy term that means "how often it happens") of blood clots in people during the year following their start of chemotherapy for cancer. It seems my anxiety was warranted. While the risk of blood clots in people without cancer who weren't going through chemotherapy (the control group) was 1.4%, the incidence in the cancer group was 12.6%.
Some factors were linked with an increased risk for clots. These included:
- The type of cancer (pancreatic cancer had the highest risk)
- Other medical conditions that people had in addition to cancer, such as obesity
- The particular medications that people were given, including chemotherapy drugs and medications given for the side effects of chemotherapy drugs (risk was increased with Platinol (cisplatin), Avastin (bevacizumab), and the red blood cell stimulator, erythropoietin)
If you're going through chemotherapy for cancer it can be helpful to know the symptoms of blood clots, as well as things you can do to lower your risk. Check out:
Khorana, A. et al. Incidence and predictors of venous thromboembolism (VTE) among ambulatory high-risk cancer patients undergoing chemotherapy in the United States. Cancer. 2012 Aug 14. (Epub ahead of print).