Choosing a Mammography Center
Is exposure to the radiation of mammography a risk?
As technology has improved over the years, the amount of radiation used in mammography has greatly decreased. Although it is true that high or moderate doses of radiation cause cell changes that can produce cancer, including breast cancer, it is not certain that routine, low-dose mammograms lead to extra breast cancers for most women. The National Cancer Institute has estimated that the radiation from routine mammography could produce one extra death from breast cancer per 10,000 women. Some radiation biologists believe that a normal immune system will repair all of the damage from regular low-dose mammograms, just as it repairs damage from the most common source of low-dose radiation, sunlight.
The risk of damage to the breasts from radiation is much higher for younger women, which is why mammography is rarely used for women under 30. Although women who have a defective cell-repair mechanism (those who carry mutations on the BRCA1 or BRCA2 "breast cancer" genes, and perhaps younger women with a family history of early breast cancer) are believed to be more susceptible to damage from radiation, the degree of extra risk (if any) is uncertain.
How do I identify a qualified mammography center?
Ask your mammography center representative if your mammogram will be interpreted by a radiologist who has special training in breast imaging. Also, find out if a facility's callback rate is more than 10%. An accredited mammography facility must record that information, even if it isn't especially eager to tell you what it is. An efficient mammography center, one in which films are interpreted by a radiologist trained to read mammograms, should have little difficulty in keeping its callback rate to 10% or less; five percent is even better.
If you know a woman who has recently had a mammogram at a facility you are considering going to, ask her how prompt the center was in communicating her results to her and her referring physician. Current U.S. law requires that a woman who gets a mammogram be informed in writing of the results -- and what they mean or do not mean -- within 30 days, and within five days if cancer is suspected. In addition, the original mammogram film must be mailed either to the woman or to her doctor, so that it can be compared with earlier films. The most efficient mammography facilities began to provide prompt written reports soon after the law took effect in the spring of 1999.
How do I make an informed decision?
Each woman should make her own decision. In locations where health policies are established after a careful review of the overall risks and benefits of screening, mammography services are generally offered every other year to women between the ages of 50 and 65 or 70. Individual women have their own preferences about risk. Health decisions are like any other decision: your desire for a specific benefit must be weighed against your desire to avoid a specific risk.
To make an informed decision about the risks and benefits of a particular screening test, you must know what those risks and benefits are; how large or small they are; and which of the risks or benefits you care about the most. A 1997 consensus conference report from the U.S. National Institutes of Health states, "Each woman should decide for herself whether to undergo mammography. Given both the importance and complexity of the issues involved in assessing the evidence, a woman should have access to the best possible information in an understandable and usable form." In Great Britain, the General Medical Council issued guidelines in 1998 for getting informed consent from a woman invited to undergo breast screening. The doctor who makes a screening invitation is expected to explain the purpose of the screening; the likelihood of positive or negative findings; the possibility of false positive and false negative results; the uncertainties and risks of screening; and any medical, social, or financial consequences.
