Cancer Center Studies Long-Term Risks of Childhood Treatment
UR Goal: Reduce Heart Disease, Second Cancers, from Radiation
Wednesday, October 06, 2004
University of Rochester Medical Center doctors are trying to improve childhood cancer treatments so that kids are less likely to develop heart problems or second malignancies later, as a result of radiation therapy.
Physicians from the James P. Wilmot Cancer Center at the UR were chosen to present two research projects on this subject, at the American Society for Therapeutic Radiology and Oncology annual meeting in Atlanta today.
In one study, Ronald Hale, M.D., chief resident in Radiation Oncology, reviewed the cases of 277 children who survived various cancers to assess whether they developed heart damage as they aged. The average age at diagnosis was 9; a complete cardiac examination measured their cardiac risk factors when they were an average age of 20.
Hale found that heart damage corresponded with larger doses of radiation. (The heart sometimes receives incidental radiation because it is in the pathway of tumors in the chest wall, lungs, neck, kidneys or spine.) The types of cardiac damage that Hale found to be associated with radiation therapy included left ventricle shrinkage, a thinning of the LV wall, and a regurgitation of blood flow in the valves. In addition, some childhood cancer survivors are at increased risk for coronary artery disease.
The National Cancer Institute funded the study. Next, Hale plans to investigate how much radiation typically gets to the heart during treatment, and what areas of the heart are most sensitive to radiation. The goal is to encourage regular screenings for heart disease in childhood cancer survivors, and to identify the dose that seems to correspond with long-term harm on the developing heart.
In another study, Louis Constine, M.D., professor of Radiation Oncology and Pediatrics, found that survivors of childhood Hodgkin lymphoma are at risk for second malignancies, and the risk increases with higher radiation doses. He studied the cases of
930 children, under 18 years old, who were treated between 1960 and 1990 at five medical institutions including the University of Rochester. About 43 percent were treated with radiation alone, and 48 percent received a combination of radiation and chemotherapy.
Overall, the childhood cancer survivors were 14 times more likely than the general population to develop a second cancer. Also, breast cancer was more prevalent among females who received higher radiation doses as children, the study found.
Doctors have made tremendous strides in treating children with cancer, both in terms of getting the disease into remission and mitigating the long-term side effects. In fact, Constine serves as vice chair of the Hodgkin’s committee of the national Children’s Oncology Group, and has worked with oncologists to develop and test new therapies that reduce toxicities.
Constine stressed that the primary focus of treatment must be to cure the malignancy. “But children need to be carefully followed by knowledgeable physicians, and some additional screening is necessary at an earlier age compared to the general population,” he said. “Fortunately, this type of multifaceted attack is already in progress. The research we are doing here at the University of Rochester allows us to further understand what needs to be done to minimize recurrences and other health problems.”
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