Most patients with a form of eye cancer called choroidal melanoma want to undergo a genetic test that can predict their likely outcome, a small study suggests.

Moreover, researchers found, those patients who get bad news from the test seem to be able to handle the emotional impact.

Of the 99 patients with choroidal melanoma in the study, 97 percent said they would have wanted the prognostic test at the time of their diagnosis. A similar percentage said patients should also receive supportive counseling when testing was done.

Among the patients who ultimately did have the test, those who received a poorer prognosis remained similar to the other patients in how they rated their quality of life and depression symptoms.

The findings are published in the Journal of Genetic Counseling.

Choroidal melanoma occurs in pigmented cells in tissue at the back of the eye. It is a rare form of cancer, but is the most common eye cancer in adults. Over time, tumors can grow and cause vision loss. The cancerous cells can also spread to other parts of the body - at which point there are no proven effective treatments, explained Dr. Tara A. McCannel, one of the researchers on the new study.

There is a genetic test available at a handful of U.S. medical centers that can predict a patient’s odds of dying from choroidal melanoma. In about half of cases, the tumor cells have only one copy of chromosome 3, rather than the normal two, and patients with a single copy (known as monosomy 3) have a heightened risk of dying from the cancer.

About half of patients with monosomy 3 see their cancer spread within five years of having the original eye tumor treated. However, testing for monosomy 3 is controversial because no good treatment exists once the cancer has spread, explained McCannel, director of the Ophthalmic Oncology Center at the University of California Los Angeles.

The current findings, she told Reuters Health, are “highly encouraging for continued efforts to get patients more involved in their healthcare.”

Even though the monosomy 3 test does not yet affect the treatment of ocular melanoma, McCannel said, it does lessen patients’ uncertainty about the future.

“They have the opportunity to plan and manage their lives accordingly,”

McCannel noted.

Right now, in most cases where genetic cancer tests are used, the point is to predict a person’s risk of developing a tumor - as in the case of the BRCA gene mutations linked to breast and ovarian cancers - or to guide treatment, as with acute myeloid leukemia.

The current findings, according to McCannel’s team, suggest that many patients also want prognostic information, even in the absence of therapies that can change their outlook.

SOURCE: Journal of Genetic Counseling, June 2009.