WASHINGTON -- Girls X-rayed during diagnosis and treatment of scoliosis -- sideways curvature of the spine that affects at least 120,000 young people -- may be at increased risk for breast cancer later in life, two government researchers said Tuesday.
The scientists said simple shielding methods could be used to protect the girls' breast tissue during scoliosis X-rays, which expose patients cumulatively to far more radiation than X-rays taken for other conditions.
'We're trying to get the message out to people who do scoliosis radiography that they really ought to be careful,' said Charles Showalter, director of the division of technical development at the Food and Drug Administration's Center for Devices and Radiological Health.
Scoliosis appears between the ages of 10 and 15, when the spine is still growing, and affects 5 percent to 10 percent of all adolescents, according to the FDA. About 120,000 are severe enough to follow up, Showalter said.
Many schools look for signs of the condition during health screening. If scoliosis is suspected, X-rays are usually taken to determine the type and extent.
About two-thirds of cases referred to physicians from schools are female, according to the FDA.
Each follow-up evaluation usually includes at least one X-ray, taken from front to back with breast tissue bearing the full brunt, the agency said. Some patients are X-rayed every three to six months from adolescence to skeletal maturity.
Breast tissue is known to be more prone to cancer following radiation, but two studies reported in 1977 that adolescent breast tissue is even more susceptible, said Alvin Thomas, a health physicist in Showalter's division.
The National Cancer Institute is conducting a study to determine how much of an increased risk of breast cancer scoliosis patients have.
In scoliosis exams, breast tissue may be exposed to a cumulative dose of as much as 14 rads of radiation or more, Thomas said. Mammography delivers one-half to one rad.
Showalter said three things can be done now to minimize the risk of breast cancer for these patients:
-Use a faster film-screen combination.
-Shield the breasts. This can be done with vests or stoles containing lead shielding over the breast area or by blocking X-rays to the breast as they leave the machine.
-'Another absurdly simple thing you can do is turn the patient around,' Showalter said, X-raying from back to front.
Although the spine would be farther from the film this way and the X-ray would be less clear, the results would be 'good enough. You don't need a great radiograph for scoliosis,' he said.
Treatment of the condition includes back braces or electric stimulation, which counteracts muscles pulling the spine out of shape, for those with greater than 20-degree curvature. For greater than 40 degrees, surgery may be required.
