Radiation treatment for eye cancer does not change patients' five-year survival rate (9/18/98)
Researchers at The University of Texas Health Science Center at San Antonio have found that study patients with large eye melanoma had similar five-year survival rates regardless of whether or not they were treated with radiation prior to removal of their diseased eye. The Health Science Center was one of more than 50 study institutions in the United States and Canada.
"There were two treatment arms: simply taking the eye out or treating the eye with radiation before removing the eye," says Bailey L. Lee, MD, assistant professor of ophthalmology at the Health Science Center. "We were hoping for a benefit with the radiation."
In the clinical trial, the Collaborative Ocular Melanoma Study (COMS), two groups of patients with tumors large enough to require removal of the eye were studied. One group received radiation treatment to the affected eye before it was removed. The other group had the eye removed without the radiation treatment. Researchers found that, after five years of follow-up study, the radiation treatment had no effect on patientsí survival rates. The COMS trial was supported by the National Eye Institute (NEI) and the National Cancer Institute (NCI), two components of the federal government's National Institutes of Health.
The type of ocular melanoma studied by researchers was choroidal melanoma, an eye tumor that forms from pigmented cells of the choroid, a layer of tissue in the back of the eye. Although it is rare, choroidal melanoma is the most common primary eye cancer in adults. Many choroidal melanomas enlarge over time and can lead to loss of vision. More importantly, tumors also can spread to other parts of the body and eventually cause death.
Researchers estimate that between 1,680 and 2,240 new cases of ocular melanoma are diagnosed annually in the United States and Canada, a rate of about six to eight new cases per million people each year. Ocular melanoma occurs in all ethnic groups, although it is more common in whites of northern European descent.
There had been uncertainty in the medical community about the value of giving radiation treatments prior to removal of the eye of patients with large ocular melanoma. In cancers occurring elsewhere in the body, prior radiation has been shown to reduce the rate of tumor recurrence after surgery. The COMS is the first controlled, randomized, multicenter clinical trial large enough to measure the survival rate of patients who had received radiation treatment prior to eye removal.
"Although survival rate is not prolonged with radiation prior to removal of the eye, the results of the study will impact the care of patients with large melanomas. They no longer will endure the inconvenience and cost of radiation treatment before removing the eye," says Dr. Lee.
A separate trial comparing two different treatments for medium-sized eye melanomas will finish enrolling patients this year.
Contact: Myong Covert (210) 567-2570