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Risk Factors for Melanoma of the Eye
Reported August 14, 2009
(Ivanhoe Newswire) -- Seven factors may predict whether a choroidal
nevus—a benign, flat, pigmented growth inside the eye and beneath the
retina—may develop into melanoma, according to a new report.
Benign choroidal nevi and small melanomas share many characteristics,
including color, location and size. "The challenge is to identify the single
small melanoma among the thousands of choroidal nevi. It has been estimated
that 6 percent of the white population harbors a choroidal nevus and that
one in approximately 8,000 of these nevi transform into melanoma," Carol L.
Shields, M.D., and colleagues at Wills Eye Institute, Thomas Jefferson
University, Philadelphia, were quoted as saying.
The researchers studied the medical records of 2,514 patients with choroidal
nevi between 1974 and 2006. The tumors had a median diameter of 5
millimeters and a median thickness of 1.5 millimeters at the beginning of
the study. Choroidal nevi grew into melanoma in a total of 180 eyes, or 7
percent, over an average follow-up of 53 months -- 2 percent after one year,
9 percent after five years and 13 percent after ten years.
The factors that predicted growth into melanoma included five previously
identified factors: tumor thickness greater than 2 millimeters, fluid
beneath the retina, symptoms such as decreased vision or flashes and
floaters, orange pigment and a tumor edge within 3 millimeters of the optic
disc. Two new factors were also identified: hollowness of the growth on
ultrasound and the absence of a surrounding halo, or circular band of
depigmentation.
"Until systemic therapies for metastastic uveal melanoma improve, our focus
should be on early detection to minimize metastastic disease," the authors
wrote. "All ophthalmologists should participate in this effort and patients
with risk factors can be referred for evaluation at centers familiar with
the nuances in the diagnosis and management of early melanoma."
Patients with choroidal nevi that do not display any of the seven features
of disease should be monitored twice yearly at first and then followed up
yearly if their condition remains stable. Those with one or two features
should be monitored every four to six months, and those with three or more
features should be evaluated at an experienced center for possible
treatment, the authors conclude.
SOURCE: Archives of Ophthalmology, August 2009 |
