The results of the Collaborative Ocular Melanoma Study (COMS), a multi-center trial released today by the Archives of Ophthalmology, found that survival rates were the same regardless of whether the eye was removed or the patient had instead undergone radiation therapy. Ohio State University is one of more than 40 centers throughout the United States and Canada participating in the study.
Traditionally, physicians have removed the affected eye in patients with this disease, said Frederick Davidorf, a professor of ophthalmology at Ohio State and a principal investigator with the COMS.
The study looked at 1,317 patients with choroidal melanoma -- or cancer of the choroid, the thin layer of vessels beneath the retina. The choroid contains most of the eye's melanocytes, cells that produce and contain pigment. The patients all had medium-sized tumors (2.5 to 10 mm in height and no more than 16 mm in diameter) - ranging from the size of a small pea to a lima bean. Removal of the eye is still the only option for patients with larger tumors, Davidorf said.
Half of the patients (657) underwent radiation therapy, while the other half (660) had their affected eye removed. Findings show that 82 percent of the former group and 81 percent of the latter group were living five years after initial treatment. Also, there was no evidence that either treatment caused harm to the unaffected eye, Davidorf said.
"This is a better-than-expected survival rate, based on information from previous studies of fewer patients," Davidorf said. "We had only expected a 70 percent five-year survival rate when we began the study 16 years ago."
Of the patients who underwent radiation therapy, 63 percent had visual acuity of 20/200 or worse in the treated eye. By five years after treatment, 12 percent had had the treated eye removed due to complications of the radiation treatment or tumor growth. The Ohio State researchers will continue to follow each patient for at least 15 years from initial treatment.
According to the National Eye Institute, between 1,600 and 2,400 new cases of ocular melanoma are diagnosed each year in the United States and Canada.
For more than a century, removal of the eye was the standard treatment for choroidal melanoma, regardless of tumor size.
"The results of this study will save many future patients the physical and mental trauma associated with the loss of an eye," Davidorf said.
Ohio State researchers began looking at radiation as an alternate therapy for choroidal melanoma as early as the late 1960s. A study co-authored by Davidorf in the January 1970 Archives of Ophthalmology found that four out of five patients with choroidal melanoma were successfully treated with radiation.
Eye care professionals typically detect melanoma by dilating a patient's pupil.