A Study Of 182K People Linked This Cancer To A 6X Higher Stroke Risk

When cancer enters the picture, there is a lot to think about. You may be focused on appointments, test results, treatment options, and simply figuring out what happens next.

Heart and brain health can easily fade into the background, especially when there is already so much to manage.

But a recent study of more than 182,000 people suggests there may be another health consideration to keep on the radar after a cancer diagnosis.

Researchers found that the risk of ischemic stroke, which happens when a blood vessel supplying the brain becomes blocked, was higher during the year that followed a cancer diagnosis.

About the study

Researchers used two national health registries, one tracking cancer diagnoses and another tracking strokes. They followed 182,221 adults ages 40 and older who were diagnosed with their first invasive cancer between 2014 and 2021.

The researchers compared their risk of having a first ischemic stroke during the following year with that of people in the general population who were similar in age, sex, and background.

They also looked at whether stroke risk differed depending on the type and stage of cancer.

Stroke risk was highest in the first three months

Overall, people who had recently been diagnosed with cancer were nearly twice as likely to have an ischemic stroke within the following year compared with the general population.

But the risk wasn't evenly spread across that year. It was highest during the first three months after diagnosis, then gradually decreased.

Cancer type also mattered. People with pancreatic cancer had about six times the expected stroke risk, while those with lung cancer had about four times the risk. Bladder, stomach, and certain blood cancers were also associated with an elevated risk, although the increases were smaller.

There was an important exception. Breast and prostate cancer, two of the most commonly diagnosed cancers, weren't associated with an increased stroke risk in this study.

Cancer stage made a difference, too.

People with localized cancer had only a slight increase in risk, while those with metastatic cancer had nearly three times the stroke risk of the general population.

The absolute risk was still relatively low. About six out of every 1,000 people with cancer experienced a stroke within a year, compared with roughly four out of every 1,000 people in the general population.

Why might cancer affect stroke risk?

Cancer can affect the body in ways that go beyond the tumor itself. One possibility is that some cancers make the blood more likely to clot.

Normally, clotting is a helpful process that stops us from bleeding after an injury.

But cancer can activate this system when there isn't an injury that needs repairing. If a blood clot forms and blocks blood flow to the brain, it can cause an ischemic stroke.

This may help explain why pancreatic and lung cancers had some of the strongest associations in the study. Inflammation related to cancer may also affect blood vessels and contribute to clotting.

The researchers also found that the relative increase in stroke risk was particularly large among adults ages 40 to 54. That doesn't necessarily mean younger people were more likely to have a stroke overall.

Younger adults generally have a lower baseline stroke risk, so an increase can look much larger when compared with their usual risk.

What to keep in mind after a cancer diagnosis

This study doesn't mean that having cancer makes a stroke inevitable.

It does suggest that cardiovascular health deserves a place in the conversation with your care team, particularly during the first few months after diagnosis.

A few things can help you stay informed and prepared:

Your treatment plan should always come first, and any exercise or lifestyle changes should fit with what your oncology team recommends.

The takeaway

The first few months after a cancer diagnosis may be an important window for watching cardiovascular health, especially with pancreatic or metastatic cancer.

Knowing the warning signs and asking your care team about stroke risk can add one more layer of protection while you focus on treatment.