Treating a rare form of eye cancer with radiation therapy can spare patients from significant vision loss, according to new research at Wake Forest University Baptist Medical Center.
The research involved 57 patients with malignant melanoma of the uvea which is the pigmented layer of the eye. The results were reported today at the American Society for Therapeutic Radiology and Oncology (ASTRO) meeting in Denver.
"These are very encouraging results," said Kathryn Greven, M.D., professor of radiation oncology and a study investigator. "The findings in this small series of patients with melanoma treated by Iodine 125 radioactive plaque confirm data obtained in a much larger, earlier study (COMS) that this procedure is effective in controlling the primary tumor, often with good visual outcomes."
Previously, the standard treatment for uveal melanoma was removal of the eye. But, the Collaborative Ocular Melanoma Study (COMS), a multicenter national trial reported in 2001 that radiation was a safe and effective alternative to removing the eye.
The current study involved plaque radiotherapy, which is the most frequently used system for delivering radiation to the eye tumor. With this treatment, a small metal shield containing radioactive seeds is sutured to the outside of the eye over the tumor. The shield is left in place until the required dose of radiation has been delivered, usually for four to five days. Several different type of radiation can be used in the seeds; this study used iodine 125.
The study found that at five years after radiation treatment, 90 percent of patients had their tumors controlled. Before treatment, patients' median visual acuity was visual acuity was 20/30 (which means they could see from 20 feet away what someone with perfect vision can see from 30 feet away). After treatment, media visual acuity was 20/60. In almost half of patients (47 percent) vision was stable after treatment. The researchers found that patients with good pretreatment vision and thinner tumors had better visual outcomes. "Our results show that radiation is an excellent option for certain patients with malignant melanoma of the eye," said Greven.
Uveal malignant melanoma is a rare tumor that occurs in only six per one million people per year in the United States. It is more common in lightly pigmented people and is rarely seen in nonwhite races.
Kathryn Greven in the radiation oncology department and Craig Greven, M.D. a vitreoretinal surgeon in the ophthalmology department have been performing this procedure at Wake Forest University Baptist Medical Center since 1989.