This website is no longer actively maintained
Some material and features may be unavailable

Answering your questions about mammograms

By Dr. Emily Senay and Laura LeBlanc

Detection lead mammographer, Toborcia Bedgood, left, prepares a screen-film mammography test for patient Alicia Maldonado at The Elizabeth Center for Cancer Detection in Los Angeles. Photo: AP/Damian Dovarganes

Following our segment last week about new studies on the necessity of annual mammograms, Need to Know spoke with experts from Memorial Sloan Kettering, the American Cancer Society, and the National Cancer Institute to answer your questions on the topic. Many of you have asked specific questions about your own unique medical situation; please understand that we cannot make specific recommendations for you online, and these questions should be discussed with your doctor. But where possible we have addressed the broader issues you have raised:

1. Is the radiation a woman is exposed to in routine mammograms dangerous? Can it cause breast cancer?

According to our experts, today’s mammography machines use a low dose of radiation — about the same amount of background radiation you are exposed to about every three months just from the world around you. The American Cancer Society says the radiation you would get from routine mammograms, even if you were to have them yearly from age 40 to age 90, would not significantly increase your risk of breast cancer. Repeated X-rays could cause problems but benefits nearly always outweigh the risk. Women should talk with their health care provider about the need for each X-ray. You should also ask about protective garments to shield parts of the body that are not in the X-ray. Always let your health care provider or technician know if there is any possibility you are pregnant.

2. Can the compression itself from a mammogram be harmful? Can it cause a tumor to spread?

The experts we spoke to say that, while there has been some speculation about whether it was theoretically possible, there is no scientific evidence that compression from a mammogram causes cancer to spread. There have been some reports of injury, mostly bruising, from excessive compression, but this is very rare. For most women, compression causes discomfort for a few seconds, and though painful, few lasting problems from it have been reported.

3. Are there any alternatives to routine mammograms?  How do ultrasound, thermography and PET scans fit into the picture? Can they take the place of mammograms in routine screening?

The experts we spoke to agreed that for women at normal risk for breast cancer there is no better routine screening tool than mammography.  Ultrasound can be used to evaluate breast problems found during physical examination or mammography but they do not replace mammography. Similarly, MRI can be used to evaluate abnormal findings and are recommended as an additional screening tool for women at high risk for breast cancer but they do not replace mammography for women at normal risk. PET scans are not used for routine screening for breast cancer but may have use in the evaluation and staging of breast cancer. As far as thermography goes, this is what American Cancer Society has to say:

“Thermography should not be used for the detection or diagnosis of breast cancer.  Several decades ago it was being considered for screening, but it was shown to be less accurate than mammography. Some websites promoting thermography also include a disclaimer saying it is not a substitute for mammography, but rather a technology that complements mammography. However, not only is there no supporting evidence for the use of thermography for screening and diagnosis, we do not have good supporting data to use thermography as an adjunct to mammography.”

4. How do risk factors such as family history, previous breast abnormalities, and testing positive for BRCA genes affect the frequency with which one should get a mammogram screening?

All the experts we spoke to said that women who think they might be at increased risk for breast cancer should consult with their doctors about when to start screening for breast cancer and how often. Find out more about specific risk factors at the National Cancer Institute and the American Cancer Society.

5. How do breast enlargement implants affect mammogram screenings?

According to the experts we spoke to, implants can hide breast tissue, making it more difficult to detect abnormalities. Although it is rare, it is also possible for a mammogram to cause an implant to rupture. However, our experts agreed that there is no better alternative screening method for women with implants than routine mammograms, and women with implants should still be routinely screened for breast cancer. If a woman has implants, she should be sure to discuss this when she schedules her mammogram and make sure her radiologist and technician are experienced in working with patients who have implants. During the mammogram itself, the implants will typically be pushed back against the chest wall so as much breast tissue as possible can be screened.