No one’s quite sure what causes uveal melanoma (UM). Unlike skin cancers, UM doesn’t seem to have any link to exposure to ultraviolet rays, although it’s most likely to strike people who are vulnerable to sun damage, like Caucasians and people with lighter eyes and lighter skin (but not lighter hair), and an inability to tan. Up to half of those affected by the disease will recover after treatment. In the other half, the cancer spreads from the eye – typically to the liver – and patient prognoses remain extremely poor despite extensive efforts to develop effective treatments.
“The median survival is probably about 2 years, and there are a number of papers out there that talk about life expectancy as short as 6 months,” said Marlana Orloff, MD, an associate professor of medical oncology at Thomas Jefferson University Hospital, Philadelphia.
But there is hope on the horizon, even if it’s not as near as patients would prefer. “Just over the last 5-10 years, we’ve gained a lot more knowledge about this disease as we try to understand how distinctly different it is, how mutations drive it, and how we can approach it using immunotherapy,” Dr. Orloff said. “I hope we’ll come up with better options for prolonging survival.”
Tracking uveal melanoma’s dangerous course
All melanomas, including UM, strike the melanocytes (cells) that provide pigment. According to a 2017 report1 in the journal Eye, “uveal melanoma is the most common primary intraocular tumor in adults with a mean age-adjusted incidence of 5.1 cases per million per year. Tumors are located either in the iris (4%), ciliary body (6%), or choroid (90%) . … As in many other cancer indications, both early detection and early treatment could be critical for a positive long-term survival outcome in uveal melanoma.”
The median age of diagnosis is 59-62 years, the report says, although non-Whites seem to develop the disease earlier.
The vast majority of patients receive treatment by plaque brachytherapy via radioactive seeds. “It’s like brachytherapy of the prostate,” said medical oncologist Rino S. Seedor, MD, of Thomas Jefferson University Hospital. “If the eye tumor is too big or invasive, they’ll cut out the eye.”
As many as 50% of patients will develop metastasis, sometimes within 2-3 years in those who have large tumors and high genetic risk, said ophthalmologist and radiation oncologist Miguel Materin, MD, of Duke University Eye Center, Durham, N.C. “There’s probably micrometastasis early in the development of the tumor,” he said. “The metastasis might develop before we or the patient knows there’s a tumor.”
Some physicians question the value of prognostic testing in patients who don’t yet show signs of metastasis, Dr. Materin said, because the findings can be grim.
Unlike his more cautious colleagues, Dr. Materin prefers to pursue testing, he said. Most patients agree to it. “It’s up to them to decide if they want to know if they have a bad prognosis,” he said, and the findings can be helpful to physicians because they provide useful genetic information about tumors.