In young people, stroke might be the first manifestation of an underlying cancer, according to the investigators, led by Jamie Verhoeven, MD, PhD, with the department of neurology, Radboud University Medical Centre, Nijmegen, the Netherlands.
The new study can be viewed as a “stepping stone for future studies investigating the usefulness of screening for cancer after stroke,” the researchers say.
The study was published online in JAMA Network Open.
Currently, the diagnostic workup for young people with stroke includes searching for rare clotting disorders, although screening for cancer is not regularly performed.
Some research suggests that stroke and cancer are linked, but the literature is limited. In prior studies among people of all ages, cancer incidence after stroke has been variable – from 1% to 5% at 1 year and from 11% to 30% after 10 years.
To the team’s knowledge, only two studies have described the incidence of cancer after stroke among younger patients. One put the risk at 0.5% for people aged 18-50 years in the first year after stroke; the other described a cumulative risk of 17.3% in the 10 years after stroke for patients aged 18-55 years.
Using Dutch data, Dr. Verhoeven and colleagues identified 27,616 young stroke patients (age, 15-49 years; median age, 45 years) and 362,782 older stroke patients (median age, 76 years).
The cumulative incidence of any new cancer at 10 years was 3.7% among the younger stroke patients and 8.5% among the older stroke patients.
The incidence of a new cancer after stroke among younger patients was higher among women than men, while the opposite was true for older stroke patients.
Compared with the general population, younger stroke patients had a more than 2.5-fold greater likelihood of being diagnosed with a new cancer in the first year after ischemic stroke (standardized incidence ratio, 2.6). The risk was highest for lung cancer (SIR, 6.9), followed by hematologic cancers (SIR, 5.2).
Compared with the general population, younger stroke patients had nearly a 5.5-fold greater likelihood of being diagnosed with a new cancer in the first year after intracerebral hemorrhage (SIR, 5.4), and the risk was highest for hematologic cancers (SIR, 14.2).
In younger patients, the cumulative incidence of any cancer decreased over the years but remained significantly higher for 8 years following a stroke.
For patients aged 50 years or older, the 1-year risk for any new cancer after either ischemic stroke or intracerebral hemorrhage was 1.2 times higher, compared with the general population.
“We typically think of occult cancer as being a cause of stroke in an older population, given that the incidence of cancer increases over time [but] what this study shows is that we probably do need to consider occult cancer as an underlying cause of stroke even in a younger population,” said Laura Gioia, MD, stroke neurologist at the University of Montreal, who was not involved in the research.
Dr. Verhoeven and colleagues conclude that their finding supports the hypothesis of a causal link between cancer and stroke. Given the timing between stroke and cancer diagnosis, cancer may have been present when the stroke occurred and possibly played a role in causing it, the authors note. However, conclusions on causal mechanisms cannot be drawn from the current study.
The question of whether young stroke patients should be screened for cancer is a tough one, Dr. Gioia noted. “Cancer represents a small percentage of causes of stroke. That means you would have to screen a lot of people with a benefit that is still uncertain for the moment,” Dr. Gioia said in an interview.
“I think we need to keep cancer in mind as a cause of stroke in our young patients, and that should probably guide our history-taking with the patient and consider imaging when it’s appropriate and when we think that there could be an underlying occult cancer,” Dr. Gioia suggested.
The study was funded in part through unrestricted funding by Stryker, Medtronic, and Cerenovus. Dr. Verhoeven and Dr. Gioia have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.