Cancer patients and survivors more than twice as likely to have fatal stroke

Cancer is the leading cause of death around the world, especially in developed countries. Cancer and stroke may occur separately in a patient, or cancer may lead to stroke via hypercoagulability, non-bacterial thrombotic endocarditis, direct tumour compression of blood vessels, or from therapy. As the survival rates of cancer patients continue to increase, it will become crucial to identify cancer survivors at elevated risk of stroke.

According to new Penn State research cancer patients and cancer survivors are more than twice as likely to die of a stroke than the general public. The risk increases with time and certain types of cancers like cancers of the breast, prostate or colorectum may boost the risk even more. The results have recently been published in Nature Communications.

Nicholas Zaorsky, assistant professor in radiation oncology and public health sciences, said the results may help physicians identify patients at risk for fatal strokes.

"Previous research has shown that most cancer patients aren't going to die of their cancer, they're going to die of something else," Zaorsky said. "A stroke is one possibility. Our findings suggest that patients may benefit from a screening program to help prevent some of these early deaths from stroke, as well as help identify which patients we could target with those preventative efforts."

According to the researchers, cancer is the leading cause of death in the United States, with stroke being the fifth leading cause. But while institutions like the American Heart Association and the National Comprehensive Cancer Network provide separate guidelines for stroke prevention and advice for people beyond cancer treatment, there is little guidance for preventing strokes in people who have or have had cancer.

Zaorsky, a member of the Penn State Cancer Institute, said he and the other researchers were interested in identifying those at the highest risk of stroke to help future prevention efforts.

The researchers used data gathered from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program. SEER includes data about cancer incidence, survival, treatment and age and year of diagnosis, and covers 28 per cent of the U.S. population.

For the current study, the researchers used SEER data on more than 7.2 million patients who had been diagnosed with invasive cancer -- cancer that has spread beyond the tissue in which it originally developed -- between 1992 and 2015.

The researchers found that out of 7,529,481 cancer patients, 80,513 died of a stroke. Males and females had equal chances of dying from a stroke, but those diagnosed with cancer at a younger age had a higher chance of a fatal stroke.

Additionally, they found that among those diagnosed with cancer before they turned 40, most strokes occurred in people treated for brain tumours and lymphomas. In patients diagnosed with cancer above the age of 40, fatal strokes were most commonly associated with cancer of the prostate, breast and colorectum.

Zaorsky said one explanation for the increased risk could be that many people who are diagnosed with cancer are in a "prothrombotic" state, which means they are more likely to form a blood clot.

"That blood clot may then go to the lungs and cause a pulmonary embolism, for example, or cause a stroke if it goes to the brain," Zaorsky said. "In general, it's an underlying theme and risk factor for a lot of cancer patients. And because certain cancers like those of the prostate, breast and colorectum are some of the most common cancers, that could also help explain that high association."

Brad Zacharia, assistant professor of neurosurgery, said another explanation may stem from the effects of certain types of cancer treatment.

"We can speculate that a subset of cancer patients are receiving chemotherapy or radiation treatments that may have a direct effect on the blood vessels to the brain and could increase stroke risk," Zacharia said. "This may be particularly true in patients with brain cancer."

The researchers added that future studies could help pinpoint mechanisms and further establish the relationship between cancer and strokes.

For further reference log on to :

http://dx.doi.org/10.1038/s41467-019-13120-6