YES, MELANOMAS CAN BEGIN IN THE EYE
Is it true that melanoma can develop in the eyes? If so, how common is it? How is it treated?
Melanomas can begin in the eye, a condition called intraocular melanoma. Treatment for intraocular melanomas used to primarily involve removing the affected eye. Now, however, radiation therapy often can be used to treat intraocular melanoma.
Melanoma is a type of cancer that develops in the cells that produce melanin, the pigment that gives skin its color. The eyes also have melanin-producing cells and can develop melanoma. Intraocular melanomas can be divided into three categories: iris melanomas, ciliary body melanomas and choroidal melanomas. These intraocular melanomas have a different molecular basis than skin melanoma. Therefore, they respond differently to treatment than skin melanomas.
Iris melanomas are the rarest form of intraocular melanoma. Because they affect the colored part of the eye, the patient or a family member usually notices these melanomas quickly. They tend to form in the lower portion of the iris and appear as a spot that’s a different color than the rest of the iris. Iris melanomas also may change the shape of the dark circle, called the pupil, at the center of the eye. Typically discovered when they are still in their early stages, iris melanomas often are treated promptly and successfully.
Of greater concern are choroidal and ciliary body melanomas. Combined, these two categories of intraocular melanomas make up the most common type of cancer that begins within the eye. The incidence is six new cases per 1 million adults in the United States each year. These melanomas are more common in Caucasians than other ethnic groups by a ratio of 11-to-1. Only 1 percent is associated with a genetic predisposition in patients with risks for other cancers, including mesotheliomas, breast cancer and some forms of skin melanomas.
Ciliary body melanomas form in the muscle fibers around the eye’s lens. Choroidal melanomas develop in the layer of blood vessels at the back of the eye. In some cases, these intraocular melanomas may not cause any signs or symptoms, growing undetected until they are in their later stages. They may be detected earlier, though, when they grow near the center of the field of vision, triggering symptoms such as poor or blurry vision, a sensation of flashes in vision or the appearance of small spots or specks (sometimes called floaters) within the field of vision.
Treatment for intraocular melanomas depends on the location and size of the melanoma. In the past, eye removal was necessary in many cases. Complete removal of the eye still is sometimes necessary for large melanomas. For smaller tumors, however, surgery to remove the melanoma, along with a band of healthy tissue that surrounds it, may be a suitable treatment alternative.
Radiation therapy also is often an effective treatment option for small- to medium-sized intraocular melanomas. The radiation may be delivered to the melanoma using a method called plaque brachytherapy. It involves placing a small disc, or plaque, containing radioactive seeds on the eye, directly over the tumor. The plaque is held in place with temporary stitches and remains over the eye for several days before it’s removed. The radiation also can come from a machine that delivers radiation therapy directly to the eye, such as proton beam therapy or gamma knife stereotactic radiosurgery.
No matter what the treatment approach, the chances of the melanoma developing elsewhere — in the remaining portion of the affected eye, in the other eye or in other parts of the body — is the same. Followup care to monitor for cancer recurrence in people who have had an intraocular melanoma is essential for 15 years after treatment.
Jose Pulido, M.D., Ophthalmology, Mayo Clinic, Rochester, Minn.
LENGTH OF BETA BLOCKER THERAPY VARIES
How long do I need to take beta blockers after a heart attack?
Your health care provider likely will consider a number of factors in making that decision. Guidelines recommend beta blocker therapy for three years, but that may not be necessary.
Beta blockers work by blocking the effects of the hormone epinephrine, also called adrenaline. Taking beta blockers reduces your heart rate and blood pressure. This eases the workload on your heart and improves blood flow.
At one point, beta blockers were used in the emergency department to limit heart muscle damage at the time of a heart attack. Current methods for treating a heart attack, which include clot-dissolving medications and surgical opening of blocked arteries — together referred to as reperfusion — improve blood flow without the risks of beta blockers. Immediate use of beta blockers, particularly high doses via IV, can be harmful in people who have decreased blood flow to their organs or whose heart muscle is already weak and pumping ineffectively.
Beta blocker therapy is recommended after emergency heart attack treatment to reduce risk of irregular heart rhythms, chest pain or another heart attack. In the past, many people have taken beta blockers for years, often indefinitely, after a heart attack. Experts are questioning whether this long-term therapy is necessary in people who don’t have heart failure, especially now that aspirin and cholesterol-lowering statin therapies have become reliable agents in managing heart disease.
Recent evidence suggests that, for most people with normally pumping hearts, beta blockers only may be beneficial in the first year or so after a heart attack.
If you’re still on a beta blocker several years after a heart attack and don’t have heart failure, talk to your health care provider about the pros and cons of your regimen.
Jorge Brenes-Salazar, M.D., Cardiovascular Disease, Mayo Clinic, Rochester, Minn. (Adapted from Mayo Clinic Health Letter)
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