New Proton Therapy Study Shows Promise in Treating Age-Related Macular Degeneration

March 3, 1999

A new clinical trial of some 50 patients with the wet type of age-related macular degeneration (ARMD) at Loma Linda University Medical Center's (LLUMC) Proton Treatment Center demonstrated control of the disease 18 months after being treated with proton therapy.

Analysis of the first 50 patients showed lesion control in 89 percent of the group, including lesions that could not be lasered because of size or location. Visual acuity improved or remained stable in 65 percent of patients 18 months following proton treatment. On average, loss of vision was zero lines on the eye chart at two years, compared to a national study that found a loss of four lines with no treatment, and a loss of three lines immediately following the standard laser photocoagulation treatment.

Since 1994, Loma Linda has treated some 125 patients with proton therapy for wet macular degeneration. For many years, proton therapy has been very effective in treating other blood vessel malformations and ocular melanoma ( eye cancers). Nearly 3.4 million people in the U.S., mostly 65 or older, suffer from the disease. With an aging American population, the number of ARMD cases is expected to rise dramatically over the next 15-20 years.

The disease appears in two forms -wet and dry. The 10-15 percent of patients with wet macular degeneration result in nearly 90 percent of the legal blindness associated with the disease. Abnormal blood vessels form at the back of the eye, leaking fluid that distorts central vision, forming lesions or dense scar tissue on the macular, causing severe and rapid vision loss. The macula is a small area in the middle of the retina that is responsible for sight in the center of the field of vision. It allows a person to see fine details straight ahead and perform tasks such as driving, reading and recognizing faces. Before the use of protons, treatment was limited to laser therapy - but it is only marginally effective and can be used on only a small percentage of those afflicted with the disease.

"With protons, there are no side effects or anything else you normally think of in radiation therapy," said Dr. Jerry Slater, vice chairman of radiation medicine at LLUMC. "There is no pain associated with this treatment. You go about your normal day's activity. The treatment takes about 10 minutes. Our aim is to preserve and stabilize vision as good as it can be for as long as possible."

Since it opened its proton center in 1990, LLUMC, located in southern, California, has treated more than 5,000 cancer patients with proton therapy. Loma Linda's continued study of protons in treating macular degeneration will determine if it is feasible to start increasing the radiation dosage. The primary advantage of protons is the precision and control of the proton beam, providing minimal damage to surrounding eye tissue.

More information on proton therapy for cancer treatment is available by calling 1-800-PROTONS (776-8667). Additional information can also be obtained from the LLUMC Web site, .

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