Limitations of Mammography,When to Get a Mammogram?

by Food and Drug Administration (FDA)

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Ensuring High-Quality Mammography

FDA first turned its focus on mammography following a 1974 Pennsylvania report. A state inspector had found that some mammography techniques used in different facilities had resulted in a few extremely high doses of radiation.

"That was the first time there had ever been any real attention paid to mammography — how it was being conducted and what was happening," says Richard Gross, recently retired from FDA's Center for Devices and Radiological Health.

In an effort to reduce the exposures, two voluntary programs were developed between 1975 and 1985 that involved industry working to improve the equipment. Mammography techniques began to change and radiation doses began to decrease.

"But we were concerned that much of the pressure to reduce the dose might have the effect of compromising image quality," Gross says. One program conducted, for example, showed that some images were found to be so bad that it would have been very difficult to detect anything. And these were issues over which FDA, at the time, had no regulatory authority and which had to be corrected within the facility. The American College of Radiology agreed to try to help correct the problem and in 1987 established its voluntary mammography accrediting program. FDA regulated the equipment, and ACR policed the facilities.

Limitations of Mammography

Despite its usefulness, mammography is not foolproof. The National Cancer Institute (NCI) says that some breast changes, including lumps that can be felt, do not always show up on a mammogram. Meg Long's tumor was one of them.

When the 56-year-old Norman, Okla., resident found a lump in one of her breasts in the middle of the night in 1988, a mammogram only hours later failed to detect any signs of the mass. NCI says if a woman's tumor at the particular time she has a mammogram is the same density as the surrounding breast tissue, it may not show up on the x-ray. Fortunately for Long, the tumor appeared on an ultrasound taken immediately following the mammogram.

In short, occasionally mammograms may miss cancer that is present or may indicate something that can turn out not to be cancerous. Because the procedure is not as sensitive for the denser breast tissue in younger women, these false readings, according to NCI, occur more often in women under age 50.

Breast implants can also impede accurate mammogram readings because silicone implants are not transparent on x-rays and can block a clear view of the tissues behind them, especially if the implant has been placed in front of, rather than beneath, the chest muscles. But NCI says that experienced technologists and radiologists know how to carefully compress the breasts to improve the view without rupturing the implant. When making an appointment for a mammogram, women with implants should ask if the facility uses special techniques designed to accommodate them. And before the mammogram is taken, they should make sure the technologist is experienced in x-raying patients with breast implants.

When Should a Woman Get a Mammogram?

Breast cancer strikes about 180,000 American women yearly and kills about 44,000, according to both the American Cancer Society (ACS) and NCI. Next to skin cancer, breast cancer is the most frequently diagnosed cancer in women in the United States. It is second only to lung cancer in cancer-related deaths. Although the risk of developing the disease increases as a woman gets older, it can occur in young women and even in a small number of men.

While there has never been a disagreement on the health benefits of annual screening mammograms for women age 50 to 69 according to ACS, there has been a split among health-care organizations about when and how often women in other age groups should get a mammogram. Current guidelines from ACS recommend women age 40 to 49 have a routine screening mammogram every one to two years, with the first one beginning at age 40.

NCI agrees that women in their 40s who are at average risk for breast cancer should have a screening mammogram every one to two years. In addition, the institute says women who are at increased risk due to a genetic history of breast cancer, or who have had breast cancer, may need to get mammograms at an earlier age and more frequently.

For example, women who carry either of two genetic mutations called BRCA1 and BRCA2 were advised in 1997 guidelines by the National Genome Research Institute to begin getting annual mammograms between the ages of 25 and 35. These women, ACS advises, should seek medical advice about when to begin having mammograms and how often to be screened.

According to NCI, many women claim they have — or don't have — mammograms based on whether or not their doctors routinely recommend them. NCI advises that if your doctor fails to remind you about routine mammograms, it is important for you to take charge of your own health care and remember to raise the issue.

"Cutting life short because I did not take charge of my health would have been such a waste," says Pfefferkorn. "The advances in treatment and early detection are there until we find a cure."

Preparing for a Mammogram

Before you schedule a mammogram, the American Cancer Society recommends that you discuss any new findings or problems in your breasts with your doctor. In addition, inform your doctor of any pertinent history, including prior surgeries, hormone use, or family or personal history of breast cancer.

When you're ready to set up your appointment, don't schedule your mammogram for the week before your period if your breasts are usually tender during this time. In that case, the best time is one week following your period.

ACS also has these recommendations:

• Do not wear deodorant, talcum powder, or lotion under your arms on the day of the exam. This can interfere with the mammogram by appearing on the x-ray film as calcium spots.
• Describe any breast symptoms or problems to the technologist performing the exam.
• If possible, obtain prior mammograms and make them available to the radiologist at the time of the current exam.
• Ask when your results will be available.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.