Other studies have shown that survivors of childhood leukemia or brain cancer are also at higher risk for cardiac dysfunction, obesity, short stature, and hormone and neurocognitive deficits. This is the first study to examine the risk to survivors for late-occurring strokes, which occur at least five years after their cancer diagnosis. Leukemia and brain tumors account for 53 percent of all cancers among children younger than 15 years of age and are annually diagnosed in more than 4,400 U.
S. children. Most patients live at least five years beyond their diagnosis to become long-term cancer survivors - 79 percent for leukemia and 73 percent for brain tumors.
The peak incidence for both leukemia and brain tumors is during vulnerable neurocognitive development, so researchers suspect that the radiation therapy typically received at such a crucial time may influence the later risk for stroke. * Compared with siblings, leukemia survivors were two to three times more likely to suffer a stroke. Brain-cancer survivors were eight to 10 times more likely to suffer a stroke.
* Patients with a history of relapse of their cancer were at a greater risk for stroke, likely a result of increased radiation treatment, the researchers concluded. The effects of late-occurring strokes, which can be life-threatening or result in permanent or severe disability, can be particularly devastating in these cases because they often hit when the childhood cancer survivors are reaching early adulthood - in their late 20s and early 30s. "Many people think, 'You're five years out from your cancer, you must be cured, and you can get on with the rest of your life.
' But these patients suddenly develop a new complication of the cancer and its treatments," Dr. Bowers said. UT Southwestern is one of 26 sites participating in the Childhood Cancer Survivors Study on long-term side effects for cancer survivors.
Children's Medical Center Dallas is also a member and contributed patients to the study. The study established a database of information on some 14,000 patients who survived at least five years after being diagnosed with cancer during childhood. The national database includes about 4,000 leukemia survivors and about 1,700 survivors of brain tumors.
Dr. Bowers has been culling through the data involving strokes, and previously discovered a greater stroke risk for survivors of Hodgkin disease. "But they are similar in important ways," Dr.
Bowers noted. "They both are most likely to occur in young childhood, and both groups also get targeted radiation therapy to the brain." The current treatment regiments for brain tumors and leukemia are aimed at reducing the use of radiation therapy, a move designed to lessen learning problems associated with radiation therapy.
"It would be interesting to see whether it may also impact the occurrence of strokes," Dr. Bowers said. Researchers are now formulating a follow-up study to identify a way of screening patients who might be at risk of having strokes, with the goal of eventually developing a preventive strategy.
Other researchers involved in the study were senior author Dr. Kevin Oeffinger, a former faculty member at UT Southwestern, now with Memorial Sloan-Kettering Cancer Center, as well as researchers from UT M.D.
Anderson Cancer Center, the Food and Drug Administration, the Fred Hutchinson Cancer Research Center, the University of Michigan, St. Jude Children's Research Hospital, and the Children's National Medical Center. UT Southwestern Medical Center, one of the premier medical centers in the nation, integrates pioneering biomedical research with exceptional clinical care and education.
Its more than 1,400 full-time faculty members - including four active Nobel Prize winners, more than any other medical school in the world - are responsible for groundbreaking medical advances and are committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide medical care in 40 specialties to nearly 89,000 hospitalized patients and oversee 2.1 million outpatient visits a year.
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