X-Rays linked to small raised cancer risk

London - Diagnostic X-rays are linked to a small raised risk of cancer but they provide very real medical benefits, researchers said on Friday.

"The wide availability of diagnostic X-rays represents one of the most important medical advances of the 20th century," said Amy Berrington de Gonzalez of Oxford University.

"However, it is generally accepted that there is some very small risk of cancer associated with any exposure to ionizing radiation."

Scientists had previously estimated a slightly higher cancer risk associated with X-rays, but the research by Berrington de Gonzalez and her colleague Sarah Darby, which is published in The Lancet medical journal, is the most detailed to date.

Using data from 14 industrialized countries on the number and type of X-rays performed and the doses of radiation, the researchers estimated the number of cancer cases linked to them.

Their findings ranged from a high of three percent in Japan and 1.8 percent in Croatia to a low of 0.6 percent in Britain and Poland.

In Britain, 0.6 percent would be the equivalent of about 700 cases of cancer out of a total of approximately 124,000 cases each year, according to the scientists.

Japan also had the highest estimated use of diagnostic X-rays in the 14 countries. There are about 1,500 X-rays taken per 1,000 people in Japan, compared to 500 per 1,000 people in Britain.

In addition to raised national risk rates the researchers also looked at specific types of cancer linked to radiation.

"For men, bladder cancer was one of the highest (cancers linked to X-rays) and that is partly because quite a lot of different X-rays expose the bladder," Berrington de Gonzalez explained in an interview.

Women had a higher raised risk of lung and colon cancers.

"Mammograms do give a small radiation dose to the breast," she said, "but for women over 50 the risks are very small."

The latest estimates are in line with earlier calculations done in 1981. These showed that about 0.5 percent of cancer deaths in the United States were attributable to diagnostic X-rays.

The new figures show the United States had a 0.9 percent attributable risk. The dose of radiation has decreased in the past two decades, but the frequency and number of different types of procedures available have increased their overall use in the country.

"The X-ray use in the U.S. has increased by about 20 percent over that time," according to Berrington de Gonzalez. -- Reuters

Brudirect.com News