Models predict heart disease, stroke risk in childhood cancer survivors

Prediction models accurately assessed the risk for heart disease and stroke later in life among patients who survived childhood cancer, according to findings published in Journal of Clinical Oncology.

“Cardiovascular disease risk predictors play a prominent role in clinical decision-making in the general population among older adults,” Eric J. Chow, MD, MPH, assistant member of the clinical research and public health sciences divisions at Fred Hutchinson Cancer Research Center, Seattle, and colleagues wrote. “Given the increased incidence of cardiovascular disease among young adult survivors of cancer, this high-risk population may benefit from early assessment with validated risk prediction models that include cancer treatment exposures.”

The researchers evaluated 13,060 patients who survived for at least 5 years after having several common types of childhood cancer. All patients had participated in the Childhood Cancer Survivor Study, and were diagnosed before the age of 21 years between 1970 and 1986. Chow and colleagues used patients’ siblings (n = 4,023) to establish the baseline population risk for ischemic heart disease and stroke. The researchers used piecewise exponential models with backward selection to estimate associations between potential predictors and stroke or heart disease, validating the models with participants from the St. Jude Lifetime Cohort Study (n = 1,842), as well as the Emma Children’s Hospital Cohort (n = 1,362).

A total of 265 survivors experienced ischemic heart disease, and 295 had strokes. A standard prediction model that included chemotherapy, radiotherapy, and sex produced risk scores with an area under the curve of 0.7 for ischemic heart disease and 0.63 for stroke, with concordance statistics of 0.7 and 0.66. In the validation cohorts, the area under the curve and concordance statistics ranged from 0.68 to 0.72 for stroke and from 0.63 to 0.66 for ischemic heart disease.

When the researchers used risk scores to form low-, moderate- and high-risk groups, patients from the Childhood Cancer Survivor Study in the low-risk groups had a cumulative incidence of less than 5%, whereas those in the high-risk groups demonstrated approximately a 20% incidence (P < .001). Among siblings, cumulative incidence was just 1% (P < .001 vs. low-risk survivors).

“We believe these validated models can be useful tools for counseling survivors of childhood cancer who have recently completed therapy, particularly among survivors with potentially modifiable cardiovascular risk factors,” the researchers wrote. “These models also provide a stronger evidence base upon which to develop and test potential screening and intervention strategies for high-risk patients, including assessing the cost effectiveness of various surveillance schedules.” – by Andy Polhamus

Disclosures: Chow reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.