Eye cancer survival rates same for radiation, excision

By Joy Bell

According to recent research released by the National Eye Institute (NEI), survival rates for two alternative treatments for primary eye cancer—radiation therapy and removal of the eye—are about the same. Emory Eye Center’s Paul Sternberg was a primary investigator in the nationwide study.

The clinical trial, called the Collaborative Ocular Melanoma Study (COMS), was conducted at 43 institutions, including medical schools, hospitals, and doctors’ offices, throughout the United States and Canada. The COMS trial was supported by the NEI and the National Cancer Institute, both components of the National Institutes of Health (NIH).

Prior to these findings, it was not known which treatment could result in lower mortality rates.

Also, as a result of the study, doctors can provide more accurate diagnoses and state-of-the-art treatments for primary eye cancer, or ocular melanoma. Mortality data from the two treatments are compared in the July 2001 issue of Archives of Ophthalmology.

“This study will have a major impact on treatment for patients with eye cancer,” Sternberg said. “First, it demonstrated that we can treat this tumor effectively with radiation and not have to remove the eye. Second, we were thrilled with the improved life expectancy in this study—an 82 percent five-year survival rate—suggesting that the skilled treatment and compulsive follow-up required by this study are critical to a successful outcome. The results of this study give us renewed optimism for patients with ocular melanoma.”

NCI Director Richard Klausner said, “The COMS findings are a striking example of the role clinical trials play in improving patient care. Without this important trial, patients would not know they have a choice between radiation and surgery for treatment of their ocular melanoma, with the same opportunity for long-term survival.”

With the data showing similar survival rates for radiation therapy versus removal of the eye, quality-of-life issues become important factors when deciding which of the two treatments is better for the individual patient, the findings conclude.

For more than a century, removal of the eye has been the standard treatment for ocular melanoma. During the past 25 years, interest in radiation therapy has increased because of the potential for saving the eye—and with it, some of the patient’s vision.

In the COMS study, patients with medium-sized tumors were studied in a randomized clinical trial to determine which of two treatments is more likely to prolong survival.

The affected eyes of one group received a form of radiation therapy called I-125 brachytherapy, in which a small plaque containing radioactive iodine pellets is placed over the tumor. The other group had the eye removed.

Approximately one-third of the patients have been followed for 10 years; more than 80 percent were followed for five years. Researchers found that the survival rates were essentially the same in the two groups. In the COMS clinical trial, researchers also found that the five-year survival rate of patients who were treated with either radiation therapy or eye removal was 82 percent, considerably better than the 70 percent five-year survival rate that had been projected when the study was designed in 1985.

Moreover, there is no evidence that either treatment harms the other eye.

The type of eye cancer studied by COMS researchers is choroidal melanoma, a tumor of the eye that arises from pigmented cells of the choroid, a layer of tissue in the back of the eye.

Although it is rare for a cancer, choroidal melanoma is the most common primary eye cancer in adults.

Choroidal melanomas enlarge over time and may lead to vision loss.

More importantly, these tumors can spread, or metastasize, to other parts of the body; once metastasis is clinically detected, death typically occurs within months.

Because there is no cure for metastatic melanoma, treatment is aimed at keeping the cancer confined to the eye. Researchers estimate between 1,600 and 2,400 new cases of ocular melanoma are diagnosed annually in the United States and Canada. The condition is much more common in whites of northern European descent.