Scientist works to reduce side effects of radiation therapy

04/18/05

WINSTON-SALEM, N.C. A Wake Forest University Baptist Medical Center researcher has received a $1.5 million grant to study whether the same drugs that fight obesity and diabetes may be able to also prevent a common side effect of cancer treatment the cognitive problems that can follow whole-brain radiation.

"Radiation is an effective treatment, but 20 to 40 percent of patients who get whole-brain radiation develop cognitive impairment within a year," said Mike Robbins, Ph.D., professor of radiation biology. "Their families and friends notice that they aren't as sharp as they used to be. The impairment is chronic and progressive."

These cognitive problems can include difficulty with concentration, language, memory and abstract reasoning.

With funding from the National Cancer Institute, Robbins will test whether drugs designed to block certain receptors in the brain can help prevent brain injury from radiation. About 175,000 cancer patients each year receive radiation treatments that target the whole brain or large areas of the brain.

Currently, there are no known treatments to prevent cognitive impairment that can result from the treatment. Robbins said that the aging American population makes it imperative to solve the problem.

"Cancer is a disease of old age, so the number of people getting whole-brain radiation will increase," he said.

Robbins says that, in essence, radiation speeds up the brain's aging process. Researchers believe the cause may be chronic inflammation or oxidative stress, which occurs when cells cannot remove free radicals, or structurally unstable cells that can damage healthy cells.

Robbins' project is based on new evidence that some of the same drugs used to treat obesity and diabetes may also prevent inflammation. In laboratory studies, he will explore the use of drugs that block peroxisome proliferator-activated receptors (PPARs). These receptors are known to control fat and glucose metabolism, and new evidence suggests they are also involved in inflammation.

Drugs already on the market are designed to treat obesity and diabetes by blocking the receptors. Robbins believes that the same drugs may be able to prevent or reduce the severity of cognitive impairment after whole-brain radiation.

"The drugs are available and we know the doses that patients can safely take," said Robbins. "If our theory is successful in the laboratory, this could easily be applied to patients. We know the drugs don't promote tumor growth, and in some cases may inhibit it."

This is one of several research projects looking for way to reduce the side effects of whole brain radiation. Robbins is also evaluating a blood pressure medication and a drug used to treat Alzheimer's disease as potential treatments for patients undergoing radiation. He has worked for more than 20 years on the effects of radiation in normal tissue.

Robbins' project is part of $4.5 million in research grants recently awarded to the Brain Tumor Center of Excellence. The goal of the center, which was formed in 2004, is to find better treatments and one day a cure for malignant brain tumors. In addition to its focus on research, the center provides a comprehensive program for patient care, and is the first center in the state to offer Gamma Knife stereotactic radiosurgery, a knifeless approach to brain surgery and radiation therapy.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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