WEDNESDAY, Jan. 7, 2015 (HealthDay News) -- Newly diagnosed cancer patients are at increased risk for stroke in the months after they find out they have the disease. And the risk of stroke is higher among those with more aggressive cancer, a new study says.
The findings come from an analysis of Medicare claims submitted between 2001 and 2009 by patients aged 66 and older who had been diagnosed with breast, colorectal, lung, prostate and pancreatic cancer.
Compared to cancer-free seniors, those with cancer had a much higher risk of stroke. And the risk was highest in the first three months after cancer diagnosis, when the intensity of chemotherapy, radiation and other treatments is typically highest, the researchers at Weill Cornell Medical College in New York City said in a college news release.
The risk of stroke was highest among patients with lung, pancreatic and colorectal cancers, which are often diagnosed at advanced stages. Stroke risk was lowest among those with breast and prostate cancers, which are often diagnosed when patients have localized tumors, the researchers said.
Cancer increases the risk of stroke independently of other stroke risk factors, such as high blood pressure and diabetes, according to the study published Jan. 7 in the journal Annals of Neurology.
The researchers didn't examine why cancer patients are at increased risk for stroke, but it's believed that cancer and its treatments affect blood vessels and the body's clotting system, causing the blood to thicken.
"These findings are relevant to patients and their care because stroke often leads to death and disability, especially if it is not quickly diagnosed and treated with clot-busting medicines," study first author Dr. Babak Navi, an assistant professor of neurology and neuroscience at Weill Cornell and a neurologist at Memorial Sloan Kettering Cancer Center, said in the news release.
"Patients and their doctors should be vigilant for symptoms and signs of stroke and should immediately call 911 if they occur. In addition, stroke is particularly relevant to cancer patients because strokes often preclude or delay cancer treatments, resulting in reduced survival," Navi said.
The new study found an association between a cancer diagnosis and risk of stroke, but it didn't prove cause and effect.
The U.S. National Heart, Lung, and Blood Institute has more about stroke.