Research Also Increases Nationwide Availability of Treatments
Researchers have found that the survival rates for two alternative treatments for primary eye cancer -- radiation therapy and removal of the eye -- are about the same. Prior to this finding, there was a question in the medical community as to whether either treatment might result in lower mortality. Also, as a consequence of this research, the capability of doctors nationwide to provide more accurate diagnoses and state-of-the-art treatments for eye cancer has been greatly expanded. Mortality data are compared in the July 2001 issue of "Archives of Ophthalmology".
"These findings are reassuring to patients with medium- sized eye tumors who have to choose between the option of radiation therapy vs. removal of the eye," said Paul A. Sieving, M.D., Ph.D., director of the National Eye Institute (NEI). "Patients now know that their choice will not impact their survival. Equally important, more information is now available about how each treatment will affect a patient's life, so patients and their doctors can make informed treatment decisions."
The clinical trial -- called the Collaborative Ocular Melanoma Study (COMS) -- was supported by the NEI and the National Cancer Institute (NCI), components of the Federal government's National Institutes of Health.
"The COMS findings are a striking example of the role that clinical trials play in improving patient care," said Richard Klausner, M.D., director of the NCI. "Without this important trial, patients would not have known that 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 vs. removal of the eye, quality of life issues become important factors when deciding which of the two treatment options is better for the individual patient. "Most patients who received the radiation therapy had some vision loss, and some eyes receiving radiation therapy were later removed because of tumor regrowth or other complications," said Stuart Fine, M.D., chairman of the Department of Ophthalmology at the University of Pennsylvania in Philadelphia and chair of the COMS clinical trial. "However, many people diagnosed with primary eye cancer may consider these problems worth risking in comparison to immediate loss of the eye.
"COMS researchers have initiated a parallel study to assess the quality of life for patients enrolled in this clinical trial," Dr. Fine said. "The findings of this study -- when released in a few years -- should provide more information on which to base a treatment decision."
For more than a century, removal of the eye has been the standard treatment for primary eye cancer, also known as 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 vision. In the COMS, patients with medium-sized tumors were studied in a randomized clinical trial to determine which of two treatments -- radiation therapy or removal of the eye -- is more likely to prolong survival. The affected eyes of one group received a form of radiation therapy called I-125 brachytherapy (pronounced BRAK-e-ther-a-pe), 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; over 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 causes harm to the other eye. All patients in the study will continue to be followed for up to 15 years.
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, choroidal melanoma is the most common primary eye cancer in adults. These tumors 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 that between 1600 and 2400 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. Choroidal melanoma is much more common in whites of northern European descent.
In June 1998, in a separate but related COMS clinical trial, researchers released results concerning whether a type of preoperative radiation therapy, called external beam radiation, prolonged life for patients whose ocular melanoma tumors were so large that removal of the eye was a medical necessity. Researchers reported that patients had similar survival rates regardless of whether their eyes were treated with external beam radiation prior to removal of the eye, or had their eyes removed without prior radiation therapy.
The COMS trials were conducted at 43 institutions, including medical schools, hospitals, and doctors' offices, throughout the United States and Canada. A list of current study centers and principal investigators is attached.
The National Eye Institute (NEI) and the National Cancer Institute (NCI) are both part of the National Institutes of Health (NIH). The NEI is the Federal government's lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness. The NCI is the Federal government's primary agency for cancer research. The NIH is an agency of the US Department of Health and Human Services.
