Childhood cancer survivors have high risk of recurrent stroke

By John Murphy, MDLinx
Published January 6, 2016

Key Takeaways

Survivors of childhood cancer have a high risk of recurrent stroke for decades after a first stroke. This risk is even higher in children who received high-dose cranial radiation, according to a study published in the August 26, 2015, online issue of Neurology.  

“We are at a point where more children are surviving cancer because of life-saving interventions,” said co-author of the study Sabine Mueller, MD, PhD, director of the University of California San Francisco (UCSF) Pediatric Brain Tumor Center at UCSF Benioff Children’s Hospital in San Francisco, CA. “Now, we are facing long-term problems associated with these interventions.”

In this retrospective study, Dr. Mueller and colleagues found that survivors of childhood cancer who have had one stroke have double the risk of suffering a second stroke when compared with non-cancer stroke survivors. The researchers also found that the main predictors of recurrent stroke in these patients were cranial radiation therapy, hypertension, and older age at first stroke—factors that could now help physicians identify high-risk patients.

The researchers analyzed data from the Childhood Cancer Survivor Study (CCSS), which tracks long-term of cancer treatment outcomes in 14,358 survivors diagnosed before age 21 between 1970 and 1986 in the United States and Canada. Of these participants, the researchers enrolled 271 respondents who reported having had a stroke, 70 of whom also reported a second one. The researchers analyzed the respondent demographics and cancer treatments to identify any potential predictors of recurrent strokes.

Overall, the rate of recurrence within the first 10 years after an initial stroke was 21%—double the rate of the general population of stroke survivors. Among patients who had received cranial radiation therapy (dose of ≥50 Gy), the rate was even higher: 33%.

Earlier research has found that cranial radiation therapy is a strong predictor of a first stroke. The exact mechanisms are not clear, but scientists speculate that high-dose radiation causes the blood vessels to constrict and encourage blockage.

“If they have one stroke, it’s not actually surprising that they have a high risk of getting another stroke,” said first author Heather Fullerton, MD, professor of Neurology and founder of the UCSF Pediatric Stroke and Cerebrovascular Disease Center. “You might use aspirin after the first stroke to try to reduce blood clots, but you’re not making those diseased blood vessels go away.”

This study could have important implications for follow-up of children with cancer. Current guidelines for screening survivors don’t specifically recommend examining diseased blood vessels, although they are visible with standard MRIs. “The radiologists are so focused on looking in the brain area where the tumor used to be that they’re not looking at the blood vessels,” Dr. Fullerton said.

Based on these findings, UCSF has updated its protocols to include screening for both blood vessel injury and modifiable stroke risk factors in these patients. “If we could identify high-risk patients, we could recommend they be followed by a pediatric stroke specialist,” Dr. Mueller said. “That will be huge in providing effective follow-up care for these children.”

In addition, hypertension independently predicts recurrent stroke in this population even though these strokes are mostly occurring in young adults, the authors noted.

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