Radiation eases shingles pain

DENVER, Oct 19, 2005 (UPI via COMTEX) -- Radiation therapy can help ease the potentially debilitating pain of shingles, researchers reported.

"Radiation is a safe and efficient therapy that could be a cost-effective alternative for patients who cannot tolerate the standard antiviral drugs usually used to treat shingles," said researcher Dr. Mohammed Suleiman, radiation oncologist at Hospital of Sion in Switzerland.

Suleiman presented the findings Tuesday at the American Society for Therapeutic Radiology and Oncology's annual meeting.

Each year, about 850,000 Americans develop shingles, a painful, blistering rash caused by the chickenpox virus. When the rash goes away, so does the pain -- usually -- but some people develop a condition called postherpetic neuralgia, an often incapacitating condition that can last for years.

Anti-viral drugs -- such as GlaxoSmithKline's Zovirax and Valtrex, and Novartis's Famvir -- may reduce the risk of PHN if started quickly after the characteristic rash of shingles develops, Suleiman said.

People with kidney problems and the elderly often cannot tolerate the drugs, however. For them, radiation might be a cost-effective alternative, he said.

Over the past 28 years, Suleiman and colleagues administered radiation to 54 men and 54 women at high risk of developing PHN due to a serious rash and severe pain in the first month after shingles appeared.

Before radiation, 106 of the patients complained of moderate or severe pain, while six months later, only 11 percent continued to suffer the lingering pain of PHN.

In contrast, studies have shown 20 percent to 25 percent of people treated with anti-viral drugs have PHN six months later, Suleiman said.

The radiation dose is only about one-tenth of that used to treat cancer, but there is a risk of radiation-induced cancer developing years down the road, he said, but added, "we have not seen any secondary cancers, even in patients treated 28 years ago."

Dr. Phillip M. Devlin, a radiation oncologist at Harvard Medical School, said the researchers present "an interesting and challenging hypothesis" that should be tested further.

Charlene Laino covers medical research for UPI. E-mail: healthbiz@upi.com

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