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Radiation may slow blinding disease
Radiation may slow blinding disease: Outside experts caution that
long-term effects are unknown
ASSOCIATED PRESS
Dec. 2 — Low doses of radiation can slow vision loss in
many patients with a difficult-to-treat condition that blinds
thousands of people every year, a researcher said. The
condition, age-related macular degeneration, affects about
170,000 Americans, usually over age 60, and affects more
women than men.
“IF THIS treatment delays progression of the condition by even
two years, it’s worth it,” said Dr. Robert Sagerman, professor of
radiation oncology at the Health Science Center at the State
University of New York, Syracuse. He presented his study
Wednesday at the annual meeting of the Radiological Society of
North America.
Radiation can be used only in the “wet” type of macular
degeneration, in which tiny blood vessels break through the
membrane behind the retina and leak blood and fluid, blurring
central vision while leaving peripheral vision intact.
The macula, in the center of the retina, is exposed to a low dose
of radiation once a day for up to two weeks, which closes off blood
vessels and stabilizes vision.
In Sagerman’s study of 146 patients, 90 percent reported that
their vision remained stable after six months, with no side effects,
he said.
Laser therapy currently is the standard — the only one
Medicare will pay for — but only 15 percent to 20 percent of
patients can have the treatment, doctors said.
LONG-TERM EFFECTS UNKNOWN
Physicians not involved in the study warned that the long-term
effects of radiation therapy are unknown. Randomized clinical trials
are needed to determine the therapy’s effectiveness before it is
recommended, said Dr. Robert Kalina, an ophthalmology professor
at the University of Washington.
Sagerman’s study had no control group — patients who get no
treatment — and participants will be followed for only two years.
“Radiation effects on blood vessels in the optic nerve and on
the retina can show up months or years after treatment,” Kalina
said. “Radiation therapy is less precise than laser treatment, so it
treats a wider area and has more potential to have harmful effects.
“I’m not saying it doesn’t work; there’s just not enough
information to say it is really a useful treatment.”
HIGH COST
Dr. Wayne Fung, a retina specialist at California Pacific Medical
Center in San Francisco, said he also believes clinical trials are
necessary. But he said he would help patients obtain radiation
therapy if they wanted it.
“I would tell them that the results so far are inconclusive and
that they would have to bear the cost,” he said.
Radiation therapy costs about $5,000, Fung said, while laser
therapy costs around $1,500, part of which could be paid by
Medicare.
Sagerman said the dosage used during treatment is low, about
one-fourth of the radiation dosage used for eye cancers. And
because patients already are older — the average age in his study
was 75 — long-term negative effects are not a top concern, he said.
He said it would be difficult to conduct a clinical trial because
the condition will certainly worsen without treatment, and nobody
wants to be in a control group.
“We have all these people getting older and losing their
eyesight who don’t want to wait for a study,” he said.
American Academy of Ophthalmology
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