Researchers seek clues to healing radiation scars
Cancer patients who suffer from a progressive, deep scarring of tissue following radiation treatment might benefit from a drug that's FDA-approved to treat vascular disease, according to a University of Rochester study published in this month's Journal of Clinical Oncology.
Results of the small, open-label drug study at the James P. Wilmot Cancer Center and National Cancer Institute showed that 85 percent of the patients experienced some improvement after taking the drug pentoxifylline for eight weeks. Researchers are designing a larger, placebo-controlled clinical trial for confirmation of those results. The drug was first tested in mice in 1995 and showed similar benefits.
"We are very encouraged," said lead author Paul Okunieff, M.D., professor and Chair of Radiation Oncology at the Wilmot Cancer Center. "Even for patients who receive only partial relief of symptoms, this brings a significant improvement in their quality of life. It can mean a change in medication from narcotics to an anti-inflammatory, or improved strength and range of motion, perhaps allowing them to drive a car again."
Radiation fibrosis is a chronic condition that occasionally develops months or years after radiation to the neck, chest wall, breast, pelvis, or limbs. It causes the tissue below the skin to tighten, resulting in poor range of motion, swelling and weakness. It can be so painful that narcotics are required to control it.
Doctors have long observed that inflammation worsens radiation scarring, and that some people are more susceptible than others. Currently there is no sure way to predict who will develop the condition, but an over-production of proinflammatory cytokines may be responsible.
Pentoxifylline is an agent that softens red blood cells, suppresses inflammation, and may improve blood flow to the scarred region of the body. It is one of several treatments being investigated to protect individuals from the harm of radiation, Okunieff said, because it seems to lower a chemical in the blood that causes radiation toxicity.
Pentoxifylline is commonly used in elderly patients who have impaired blood vessel function.
The National Institutes of Health funded the clinical trial, which enrolled 30 patients; 27 completed the study. Patients took 400 mg of pentoxifylline orally for eight weeks. The most common side effects were nausea, jitteriness, insomnia, headaches and dizziness. Of the 27 patients, 22 responded to pentoxifylline with improvement in at least one area in which they had symptoms: weakness, range of motion, or pain. But the response was not consistent. In a few cases, symptoms worsened. Doctors believe this could be the result of long-standing fibrosis and its potential to be irreversible in some cases, the study said.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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