Using a relatively new way to test for blockages in the heart's arteries as a general screening exam could lead to more than thousands of new cases of cancer in the US, according to a new study in the Archives of Internal Medicine.

The authors of the study note that one set of guidelines recommends testing all men without heart disease symptoms aged 45 to 75 years, and all women without symptoms aged 55 to 75 years using the method, known as multidetector computerized tomography, or MDCT.

That set of guidelines, known as the SHAPE guidelines, while not universally endorsed, could mean testing tens of millions of people, write Dr. Kwang Pyo Kim, from the National Cancer Institute, Bethesda, Maryland, and colleagues.

Because of the wide variation in the estimated radiation dose, the estimated risk of cancer also varied widely. If a man were to be screened every 5 years from 45 to 75 years of age; or a woman from 55 to 75 years, the estimated excess lifetime risks of cancer would range from 14 to 200 and 21 to 300 per 100,000 men and women, respectively.

Put another way, that could mean about 5,600 individuals developing a radiation-induced cancer in the future, the authors write. They note that proponents of MDCT as a screening test argue that their guidelines could prevent 24,000 deaths if patients followed a standard prevention strategy.

Healthcare providers should ideally discuss the potential risks and benefits of the procedure, Dr. Raymond J. Gibbons and Dr. Thomas C. Gerber, from the Mayo Clinic, Rochester, Minnesota, comment in a related editorial. This discussion should include the small radiation risk described by Kim et al.

SOURCE: Archives of Internal Medicine, July 13, 2009.