Mammography (ma-MAH-gruh-fee) is a screening tool that uses X-rays to create images of the breast. These images, called mammograms (MAM-o-grams), are used to find early signs of breast cancer such as a dense mass or clusters of calcium (microcalcifications).
Mammography is the best screening tool for breast cancer used today. It can find cancers at an early stage, when they are small (too small to be felt) and the chances of survival are highest.
Learn about mammography recommendations for women at average risk or recommendations for women at higher risk of breast cancer.
Mammograms can be done in:
Before your mammogram, you will undress from the waist up, so it is a good idea to wear a shirt you can remove easily. Avoid using deodorants, antiperspirants, perfumes, powders or lotions on the breast and underarm areas on the day of the exam. Ingredients in these products can show up on a mammogram and make it harder to interpret.
Getting a screening mammogram takes about 15 minutes. During the procedure, each breast is pressed between two plates and an X-ray image is made. Two views of each breast are taken, one with the X-ray beam aimed from top to bottom and the other from side to side.
Sometimes, the pressure can be uncomfortable, but it only lasts for a few seconds. If you have concerns, talk with your health care provider about taking acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) about an hour before the exam. He/she can also discuss other ways to help ease discomfort (or anxiety) during a mammogram. Before the exam, let your technologist know your concerns and tell him/her if you feel any discomfort during the exam.
X-ray images of the breast can be captured on film or stored directly onto a computer (digital). Film and digital mammography are similar in their ability to detect breast cancer [1-3]. Most centers now use digital mammography.
Because digital images are viewed on a computer, they can be lightened or darkened, and certain sections can be enlarged and looked at more closely. This ability to control the images on a computer makes digital mammography more accurate than film mammography for some women. And, because the images are stored on a computer, they can be shared more easily with another radiologist for review.
Compared to film mammography, digital mammography appears to be better at detecting breast cancer in women who :
For women who do not fall in one of the above groups, digital and film mammography are similar in their ability to find breast cancer early.
A radiologist trained to read mammograms will examine your images for signs of breast cancer. Computer-assisted detection (CAD) software was developed to help radiologists find suspicious areas on a digital mammogram (or film converted to a digital image). CAD software analyzes the images and highlights potential areas of concern that should be looked at more closely. It is commonly used in the U.S.
Some studies suggest CAD may improve breast cancer detection [4-5]. However, the largest study to date showed CAD did not improve the detection of invasive breast cancers . The authors also found CAD led to an increase in false-positive results . Thus, the benefit of CAD needs more study.
Learn more about false-positive results on screening tests.
Mammogram images appear in shades of black, gray and white, depending on the density of the tissue (see images below). Very dense tissue, like bone, shows up as white on an X-ray. Fat looks dark gray on an X-ray. Breast cancer and some benign (not cancer) breast conditions are denser than fat and appear a lighter shade of gray or white on an X-ray image.
Dense breast tissue can look white or light gray on a mammogram. This can make mammograms harder to interpret in younger women, who tend to have denser breasts. After menopause, breast density decreases, making the mammograms of postmenopausal women easier to read.
These mammography images show varying breast density. They show breasts with more fat and less breast tissue to breasts with less fat and more breast tissue.
Some younger women may have lower breast density after an oophorectomy (removal of the ovaries) or hysterectomy (removal of the uterus). And, women who use menopausal hormone therapy (MHT) often have higher breast density until they stop using MHT.
For women with dense breast tissue, digital mammography is more accurate than film mammography .
Ultrasound and breast MRI (in combination with mammography) are being studied to learn whether they improve detection in women with dense breasts compared to mammography alone.
Learn more about ultrasound and breast MRI.
Learn about breast density and breast cancer risk.
Some common benign breast conditions (such as cysts and fibroadenomas) may show up on mammograms as round or oval patches with distinct borders.
Learn more about benign breast conditions.
Calcifications are bits of calcium that can show up on mammograms as small, bright white spots. Most calcifications are benign (not cancer). However, certain patterns of calcifications are suspicious and need more testing. Tight clusters or lines of tiny calcifications (microcalcifications) can be a sign of breast cancer.
Calcifications are common and appear on about half of all mammograms of women ages 50 and older (and on about one in 10 mammograms of younger women) . They may be related to older age, past injury to the breast or inflammation (swelling) of the breast tissue (from an infection, for example) . For breast cancer survivors, calcifications can also be related to past breast surgery and radiation therapy.
Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer (learn more). On a mammogram, DCIS usually looks like a cluster of microcalcifications. It can be hard to know from a mammogram image whether the cluster is DCIS or invasive breast cancer.
Learn about follow-up after an abnormal mammogram.
Learn more about DCIS.
Invasive breast cancer cells appear as a light patch on a mammogram. They do not stay within the clear borders, but instead invade the surrounding tissue. The outer edges of the cells that have spread into the surrounding breast tissue look fuzzy or spiky (called spiculated).
Learn about follow-up after an abnormal mammogram.
If a finding is abnormal, or the mammography image was not clear enough to interpret the results, you will be called back for a follow-up visit. Follow-up may include another mammogram, an ultrasound or a breast MRI. In some cases, a biopsy may be needed.
The recall rate of a mammography center is the percent of women who are called back for further tests. Some centers may share their recall rate with you and this information may help you understand your chances of being called back. It is not uncommon to be called back for an abnormal finding. Although there is no “gold standard” recall rate, on average, 10 percent of women are called back .
If you are called back, don’t panic. Most abnormal findings are not breast cancer.
Learn about follow-up after an abnormal mammogram.
Most mammography centers report the results of mammograms using the Breast Imaging Reporting and Data System (BI-RADS®). BI-RADS® was developed by the American College of Radiology to provide a standard way to describe the findings on mammograms (with categories numbered 0 to 6).
Learn more about the BI-RADS® categories for mammography findings.
Some centers may give you the results of your mammogram at the time of your screening. However, depending on the center, it may take up to two weeks to get your results.
If you do not get your results within two weeks, follow up with your health care provider or the mammography center. Don’t assume the results were normal because you haven’t gotten a report.
Mammography is a safe and effective screening tool for women who have breast implants. However, the implants can make it harder to interpret the mammogram. So, if you have implants, it is important to tell the technologist before the procedure. The mammography machine must be specially adjusted to get the best image of the natural breast tissue. Special positioning of the breast may also be required. Four views of each breast will be taken (instead of the standard two).
If possible, choose a center with technologists and radiologists who are experienced in mammography for women with breast implants.
Screening mammography should not be used in pregnant women. Learn about breast cancer during pregnancy.
While you are breastfeeding, the tissue in your breasts may appear dense on a mammogram, making it hard to interpret. So, it is best to wait until you stop breastfeeding to get a routine screening mammogram. Discuss the best timing of your mammogram with your health care provider if you are due for screening.
If you have any concerns about your breasts while you are breastfeeding (such as finding a lump or noting a change), see your provider.
Some women with physical disabilities have trouble finding a mammography center that meets their needs. Partnering with a health care provider in your search can help things go more smoothly. If access to mammography for disabled women is limited in your area, let your local medical centers know. This may help improve access for you and other women.
Learn more about women with physical disabilities and breast cancer screening.
What is Susan G. Komen doing?
Since 2009, Susan G. Komen and the American Association on Health and Disability (AAHD) have been working together to address and remove barriers to screening and treatment for women with disabilities. To address these issues, Komen and AAHD launched Project Accessibility: Removing Barriers for Women with Disabilities which aims to improve access to care for women living with disabilities in our nation’s capital. Komen and AAHD recently developed a free, online Breast Health Accessibility Resource Portal with materials to help Komen grantees around the globe improve their ability to care for women with disabilities. Through Project Accessibility USA, we are changing the status quo for women with disabilities and ensuring access to quality breast cancer care for all.
Read our blog on Project Accessibility.
To learn more about Project Accessibility USA, please contact firstname.lastname@example.org.
A woman is exposed to a small amount of radiation during a mammogram. While the radiation exposure during mammography can increase the risk of breast cancer over time, this increase in risk is very small [9-10]. Studies show the benefits of mammography outweigh the risks from radiation exposure, especially for women ages 50 and older [9-11].
Although a recent report suggested radiation during a mammogram might increase the risk of thyroid cancer, there is no scientific research to support this claim .
Medicare, Medicaid and most insurance companies cover the cost of mammograms. As of September 23, 2010, as part of the Affordable Care Act (health care reform), all new health insurance plans are required to cover mammography (with no co-payment) for women ages 40 and older.
In many parts of the U.S., low-cost or free mammograms are offered through national programs and community organizations.
Each October, during Breast Cancer Awareness Month, many imaging centers offer mammograms at reduced rates. To find a certified mammography center in your area, visit the FDA website (www.fda.gov).
After mammography was shown to be an effective breast cancer screening tool in the late 1980's, the use of screening mammography in the U.S. quickly increased. In 1987, 29 percent of women 40 years and older reported having a mammogram within the past two years . By 1990, use increased to 52 percent and by 2000, 70 percent of women 40 years and older reported having a recent mammogram . After a slight decline in mammography use from 2000 to 2005 (for reasons that remain unknown), rates remained steady. Since 2008, rates may be slightly increasing [13-14]. In 2010, 67 percent of women 40 years and older (67 percent of white women, 66 percent of African American women and 64 percent of Hispanic/Latino women) reported having a recent mammogram .
Learn about disparities in screening mammography.
Learn more about the accuracy of mammograms now or read about the recent conversations and debate surrounding mammography.
Facts for Life: Mammography
Questions to Ask Your Doctor, Mammography
Facts for Life: Breast Calcifications
Facts for Life: Breast Density
Facts for Life: Women with Disabilities