Using a new calculation to estimate the risk of cancer from exposure to diagnostic X-rays, Amy Berrington de González, of the University of Oxford, United Kingdom, and Sarah Darby, of Cancer Research UK, suggested in a recent article that in the UK around 700 of the 124,000 cases of cancer diagnosed annually could be attributable to exposure to diagnostic X-rays. The article appeared in the Jan. 31, 2004, issue of The Lancet.

The authors’ estimate of around 700 additional cancer cases annually in the UK is equivalent to a cumulative risk of cancer to age 75 years of about 0.6 percent. That number rises to 3 percent in Japan, they calculated, the country with the highest estimated annual X-ray use in the world. Berrington de González and Darby concluded that, “although there are clear benefits from the use of diagnostic X-rays, that their use involves some risk of cancer is generally acknowledged. We provide detailed estimates of these risks.” Because some of their calculations depended on assumptions, the results were somewhat uncertain.

Peter Herzog and Christina Rieger from Ludwig-Maximilians University Munich, Germany, stated in an accompanying commentary, “Berrington de González and Darby did not assess the indications or benefits achieved for patients in X-ray examinations. Benefits include the earlier detection of cancers by radiological examinations and the possibility of early treatment, which probably allows more cure of cancers than radiological exposure is able to cause.”