Study shows diagnosis of cancer is associated with more than doubling risk of stroke as it increases risk of blood clots.
Patients with cancer have higher risks of heart attack and stroke from blood clots, especially in the first few months after diagnosis, compared with people who don't have cancer, researchers report.
"A new diagnosis of cancer is associated with more than a doubling in risk of stroke and heart attack in the first six months after cancer diagnosis,” Dr. Babak B. Navi from Weill Cornell Medicine in New York City told Reuters Health by email. “Therefore, cancer patients and their doctors need to pay more attention to the potential secondary complications of cancer and its treatments, particularly the cardiovascular ones, which are associated with substantial morbidity and mortality.”
Cancer increases the risk of blood clots, but most earlier studies reported on the risk of deep-vein thrombosis and pulmonary embolism, not on clots in the arteries (where they cause heart attacks and strokes).
Navi's team used information from a Medicare-linked database to evaluate the risk of heart attack and stroke in patients age 66 or older with new diagnoses of eight cancer types: breast, lung, prostate, colon, bladder, pancreas, stomach and non-Hodgkin lymphoma. They compared the cardiovascular risks in the cancer patients to risks in similar people without cancer.
Six months after diagnosis, people with cancer had a higher rate of heart attack or stroke (4.7%) due to blood clots than people without cancer (2.2%), the authors reported in the Journal of the American College of Cardiology, online August 14.
The rate was highest in patients with lung cancer (8.3%) and was generally higher in patients with the most-advanced cancers. But even patients in the earliest stages of cancer had an increased risk of stroke and heart attack.
After the first six months, the differences in risk got smaller, and by one year after diagnosis, the risks were about the same in people with, versus those without, cancer.
The risk of dying within 30 days after a stroke or heart attack was also greater in cancer patients (17.6%) than in patients without cancer (11.6%).
“This suggests that all cancer patients, even those with localized disease, should be monitored for signs and symptoms of cardiovascular disease,” Navi said. “I recommend that patients with newly diagnosed cancers have frank discussions with their doctors about their individual risks of myocardial infarction and stroke and that they should work with these doctors to aggressively target any known cardiovascular risk factors.”
Dr. Edward T. H. Yeh from University of Missouri, Columbia, Missouri, who coauthored an editorial related to this report, told Reuters Health by email, "Based on the early myocardial infarction and stroke risk in cancer patients, it is important for the oncologist to refer patients with cardiovascular risk factors, such as diabetes, high cholesterol, and hypertension, to cardiologists or internists for risk-factor modification. Patients with cancer should also be aware of the signs and symptoms of acute coronary syndrome and stroke. They should seek immediate medical attention following the onset of new symptoms.”
“Successful cancer treatment should also include prevention of cancer or cancer therapy-associated adverse events,” he said. “Cancer patients should be co-managed with cardiologists or other specialists to improve clinical outcomes.”