Cancer survivors have unique and long-term cancer-specific side effects.

Patients surviving childhood Hodgkin disease suffer strokes later in life at rates about four times that of the general population, UT Southwestern Medical Center researchers have found.

Principal investigator Dr. Daniel Bowers, assistant professor of pediatrics, and other UT Southwestern researchers identified the link using patient information from a national database of long-term childhood cancer survivors. The study, which appeared in the Journal of Clinical Oncology, is available online.

"We were surprised. We knew there was increased risk of a second cancer - usually breast cancer - and increased risk of heart failure, but stroke was unexpected," said Dr. Bowers.

Although doctors cure about 70 percent of pediatric outpatients with cancer, little research had linked strokes later in life to cancer. Testing that hypothesis on all survivors of childhood cancer was too impractical, so the UT Southwestern research team narrowed the field to survivors of Hodgkin disease, a type of lymphoma that's the second-most common form of childhood cancer.

"The goals are changing to more than just curing the child of cancer," Dr. Bowers said. "They are to evaluate and reduce the long-term side effects. It's been well-established that childhood cancer survivors have several well-described long-term side effects, including second cancers, learning problems, growth problems and heart damage."

UT Southwestern is a member of the Childhood Cancer Survivor Study, a national consortium tracking the long-term effects of cancer survivors. Children's Medical Center Dallas is also a member and contributed patients to the study. The National Institutes of Health-sponsored study involves 27 institutes and the statistical histories of some 20,000 childhood cancer survivors.

From that database, researchers identified 1,926 people who had survived Hodgkin disease more than five years after being diagnosed between 1970 and 1986. Dr. Bowers and other researchers identified 24 Hodgkin disease survivors who later reported a stroke and compared that to the siblings of cancer survivors, where only nine of more than 3,800 had suffered strokes. The incidence of strokes – 83.6 per 100,000 person-years for Hodgkin disease survivors and 8.0 per 100,000 person-years for the control group – demonstrated that Hodgkin disease survivors were at significantly increased risk of suffering a stroke.

"With the high visibility of stories like Lance Armstrong, people think that if you're a cancer survivor you're cured, and you have no further problems, and you can go ride in the Tour de France," Dr. Bowers said. "And maybe that's true for some people. But we are clearly recognizing that cancer survivors have unique and long-term cancer-specific side effects. People are beginning to look at quality of life."

The UT Southwestern research may support other studies suggesting the need to reduce the amount of radiation used in treatments for Hodgkin disease, he said.

"The next generation of studies will be able to look at the question: Does a reduction in radiation dose cause a decrease in the frequency of stroke?" Dr. Bowers said. "It certainly would be a logical expectation, but we don't know that."

Other researchers involved in the study were senior author Dr. Kevin Oeffinger, a former family practice professor at UT Southwestern, now with the Memorial Sloan Kettering Cancer Center, and researchers from UT M.D. Anderson Cancer Center in Houston, the Food and Drug Administration, the University of Minnesota, St. Jude Children's Research Hospital in Memphis, Tenn., Stanford University School of Medicine, Children's National Medical Center in Washington, D.C., and the Childhood Cancer Survivor Study.