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Frequently Asked Questions About Mammography and Breast Cancer

Notice: Revised breast cancer screening guidelines issued in November 2009.

What is a Mammogram?

A mammogram is a special type of x-ray imaging exam used to create detailed images of the breast. Mammography uses low dose x-ray; high contrast, high-resolution film; and an x-ray system designed specifically for imaging the breasts. In the case of digital mammography, the system is equipped with a digital receptor and a computer instead of a film cassette. Mammography plays a major role in early detection of breast cancers, which in turn, increases the chances of successful treatment and survival. The U.S. Food and Drug Administration (FDA) reports that mammography approximately 85% of all breast cancers and can detect cancer several years before a lump can be felt. Learn more about mammography.

Why is Mammography Sometimes Uncomfortable?

Patients will feel firm pressure but no significant pain. If you feel discomfort, please inform the technologist. The quality of your mammogram is greatly dependent on compression of the breast, which may sometimes cause discomfort (the discomfort is brief). Compression decreases breast motion that can cause blurry images. Thicker breast tissue also causes x-ray scatter and that degrades images. The total x-ray dose to the breast is greatly reduced by good breast compression. Breast compression also flattens the breast so that all of the tissue can be visualized in the image.

When Should I Get a Mammogram?

The National Cancer Institute recommends women 40 years of age receive a screening mammogram every one to two years. Begininning at age 50, mammography should be performed every year. Patients at high risk of breast cancer (especially those with a strong family history of breast cancer) should consult their doctor about beginning annual mammograms prior to age 40. Depending upon the results of a screening mammogram, or as part of follow up to a diagnostic mammogram, women may need to come back for additional mammography and diagnostic testing on a more frequent basis. Consult your doctor.

Do I Need a Referral (Prescription) to Receive Mammography?

No, many centers that perform mammography allow women over 40 to simply call and make an appointment for a screening mammogram without requiring a referral (prescription) from a physician.

The center performing the screening mammogram will need the name of the patient's physician to whom the mammography report can be sent. Thus, the patient can be assured of obtaining a corresponding clinical breast examination (CBE). Further, if an abnormality is found, the patient's physician will be able to set an avenue for proper follow-up.

Diagnostic mammography is usually done based on abnormalities found with screening mammography, or for women who have a breast complaint (symptom of breast irregularity). Diagnostic mammography requires a physician referral.

Does a Mammogram Take the Place of a Manual Breast Examination?

No. The best chance a woman has for early detection of breast cancer is to combine periodic mammograms with manual breast examination by an experienced doctor. The manual exam and the mammogram complement one another to offer most comprehensive defense against breast cancer. A woman should also continue her monthly self-examination.

What is a Baseline Mammogram?

A baseline mammogram is the set of images used as the basis for comparison in later tests. It is usually a patient's first screening mammogram, unless those films are unavailable. Patients should always try to keep track or when and where they have had each mammogram. Previous mammograms are necessary to assist the interpretation of current or future mammograms. Patients who do not have a baseline mammogram are more likely to need extra views, follow up exams and biopsies. If prior mammograms are available for comparison, less additional study and examination is needed.

How Long do Mammography Examinations Take?

This can vary from center to center, but once patients are called, screening mammography usually takes less than 15 minutes. Diagnostic mammography takes roughly twice as long (approximately 30 minutes). Breast biopsy procedures usually take about an hour.

What is a Cleavage View?

A cleavage view (also called "valley view") is a mammogram view that images the most medial (central) portions of the breasts. This is the portion of breast tissue "in the valley" between the two breasts. When one breast is imaged and the other breast is left out of the compression field, some of the breast being imaged may get pulled or left out too. To get as much medial tissue as possible, the mammogram technologist will place both breasts on the plate at the same time to image the medial half of both breasts.

A cleavage view may be performed when there is a questionable density on the medial edge of the mammogram film and the radiologist needs to see more of this density (if possible). A cleavage view may also be performed if the radiologist sees something suspicious in the mediolateral-oblique (MLO) mammogram view and cannot find the area on the cranial-caudal view (CC) view. Learn more about views taken during mammography.

Do I Need a Mammogram if I have Breast Implants?

Yes, women with breast implants should follow the same ACR program of recommended screening mammograms as women without breast implants. However, due to the implant, several special views must be taken to allow visualization of both the breast tissue and the implant. For this reason, diagnostic mammography is always performed on patients with breast implants. Patients with implants should always inform the physician and the technologist performing the exam that they have implants. MR imaging can also be used to image breast tissue and implants, and MR is useful for checking the condition of implants. MR imaging is the imaging method of choice to evaluate the implant itself (to check for ruptures) while mammography is still the best test for evaluating breast tissue. Mammography does not cause implant rupture.

The x-rays used for mammographic imaging of the breasts cannot penetrate silicone or saline implants well enough to image the overlying or underlying breast tissue. Therefore, some breast tissue will not be seen on the mammogram, as it will be covered up by the implant. In order to visualize as much breast tissue as possible, women with implants undergo four additional views as well as the four standard images taken during diagnostic mammography. In these additional x-ray pictures, called implant displacement (ID) views, the implant is pushed back against the chest wall and the breast is pulled forward over it. This allows better imaging of the forward most part of each breast. The implant displacement views are not as successful in women who have contractures (formation of hard scar tissue around the implants). The ID views are easiest to obtain in a women whose implants are placed underneath (behind) the chest muscle.

Can X-ray Mammograms Cause Cancer?

Modern mammography uses the lowest possible dose of x-rays. Scientific data has shown that doses 100-1000 times greater those used for mammography are required to show any statistical increase in breast cancer frequency. There is no significant risk of radiation damage to breast tissue from mammography and the potential risk is greatly outweighed by the benefit of getting regular mammograms. The MQSA (Mammography Quality Standards Act) was created by the American College of Radiology (ACR) and passed by Congress to mandate rigorous guidelines for x-ray safety during mammography. Patients should make sure they are being imaged at an ACR accredited facility using modern mammography systems.

Where Can I Find a Mammography Facility?

To date, over 11,000 mammography facilities have been accredited by the American College of Radiology (ACR) in the U.S. The Center for Devices and Radiological Health of the US Food and Drug Administration (FDA) maintains a Mammography Site Database that lists mammography locations within the fifty U.S. states and Puerto Rico. Users may search for a nearby facility by entering the first three digits of their zip code.

How Much does a Mammogram Cost?

The average cost of a mammogram is approximately $100. Most insurance plans cover the cost of screening mammograms, and many facilities offer low-cost or financial assistance for those who qualify.

How Often Should I Receive a Mammogram?

The National Cancer Institute recommends women 40 years of age receive a screening mammogram every one to two years. Begininning at age 50, mammography should be performed every year. Women at a very high risk of breast cancer (such as those have tested positive for mutations of the BRCA1 or BRCA2 breast cancer genes) should speak with their physician about beginning annual mammograms as early as age 25.

Why Aren't Mammograms Recommended for Women Under Age 40?

Physicians do not generally recommend that women under age 40 receive annual screening mammograms because younger women tend to have more dense breast tissue. This breast density shows up on mammogram films as white areas, just as breast cancer does. Therefore, it is difficult for physicians to detect breast cancer in women with dense breasts. As women reach menopause, their breasts become less dense, making it easier to interpret their mammograms. Women under age 40 should still practice monthly breast self-exams and receive physician-performed clinical breast exams at least every three years. If an abnormality is detected with physical exam in a patient of any age, she may receive a diagnostic mammogram, ultrasound or other breast imaging exam to further investigate the abnormality.

Why Aren't Ultrasound, MRI, or Other Tests Used to Screen for Breast Cancer?

Currently, mammography is the only exam approved by the U.S. Food and Drug Administration (FDA) to help screen for breast cancer in women with no signs of the disease (such as a lump). Mammography helps detect approximately 85% of all breast cancers and has contributed to a 2% annual decline in breast cancer deaths in the past 10 years. While ultrasound, magnetic resonance (MRI) breast imaging, and other tests may be helpful when further investigating an abnormality first detected with mammography or physical exam, these supplemental exams are not FDA approved as screening tools because of the limitations listed the chart below.

Exam Pros Cons
Ultrasound Good contrast resolution, excellent for identifying non-cancerous cysts or dense mass. Lacks spatial resolution, operator dependent, cannot detect calcifications (may indicate cancer).
Breast MRI Good at imaging dense breasts, implants or small lesions, helps stage extent of cancer. Long and costly exam, difficult to differentiate between cancerous and benign lesions, cannot detect calcifications.

Why is Mammography Not 100% Accurate?

It is estimated that mammograms can detect approximately 85-90% of all breast cancers. While the vast majority of abnormalities are detected by mammography, there are some that are simply not detectable. Sometimes an irregularity goes undetected because surrounding breast tissue is the same density as the irregular tissue. The goal of mammography is to try to identify women who have breast cancer but are unaware of it (asymptomatic women). If a patient has a lump or other change and the mammogram is "negative" (interpreted as not suspicious or cancerous), the patient should pursue that finding further with her doctor. In some cases, a lump that is not suspicious on a mammogram may be followed up with clinical breast exam or a follow-up mammogram in six months instead of the normal twelve.

A negative mammogram report should not be interpreted as meaning that there is no chance of breast cancer. It also does not mean that the breasts are "normal". Many (if not most) breasts contain "abnormalities" such as calcifications or masses. It is only when these areas show changes sufficiently different from the average patient that the mammogram is interpreted as "abnormal." That is why regular mammography and comparison with prior films is critical.

Breast cancer starts as a few malignant cells and generally takes years to grow to a detectable state. Often, radiologists may watch an area on a mammogram for change over several years to demonstrate that an initially benign-appearing area has a reasonable chance of malignancy that requires biopsy. To remove the uncertainty in determining whether each area is benign or cancerous would require many more biopsies to be performed. Performing more biopsies would add a great deal of worry, discomfort, and potential complications to a large number of women (who do not have breast cancer) while only detecting a very small number of additional cancers.

Is Digital Mammography Better Than Standard Film Mammography?

One of the most recent advances in x-ray mammography is digital mammography. Digital (computerized) mammography is similar to standard mammography in that x-rays are used to produce detailed images of the breast. Digital mammography uses essentially the same mammography system as conventional mammography, but the system is equipped with a digital receptor and a computer instead of a film cassette. Studies of digital mammography and standard film mammography have shown that digital mammography is "comparable" to standard film mammography in terms of detecting breast cancer. To date, studies have not shown that digital mammography allows radiologists to detect more breast cancers than if they use standard mammography systems.

In the future, digital mammography may provide many benefits over standard mammography equipment. These benefits include:

  • improved contrast between dense and non-dense breast tissue
  • faster image acquisition
  • shorter exam time
  • easier image storage
  • physician manipulation of breast images for more accurate detection of breast cancer
  • transmittal of images over phone lines or a network for remote consultation with other physicians

While digital mammography is quite promising, it still has additional hurdles to undergo before it can become a suitable replacement for standard film mammography. Digital mammography must: provide higher detail resolution (as standard mammography does), become less expensive (digital mammography is currently several times more costly than conventional mammography), and provide a method to efficiently compare digital mammogram images with existing mammography films on computer monitors.

What Does "in situ" Mean?

The term "in situ" is used to indicate an early stage of cancer in which a tumor is confined to the immediate area where it began. Specifically in breast cancer, in situ means that the cancer remains confined to ducts or lobules, and it has neither invaded the surrounding tissue in the breast nor spread to other organs in the body.  Ductal carcinoma is situ (DCIS) is the most common type of non-invasive breast cancer.

What are Metastases?

Metastases are satellite tumors that indicate a breast cancer has spread from the site where it began (referred to as the primary cancer) to a lymph node or a distant organ, such as the lung, liver, or brain.

What are Calcifications?

Calcifications (also called microcalcifications) are mineral deposits in the breast that may be caused by dried-up secretions, trauma to the breast, resorbed blood, or dead tissue cells. These small calcium deposits are often found in clusters by a mammogram. Dietary calcium levels do not have any relationship to breast calcifications. If a woman has calcifications in the breast she may continue calcium supplements which can be helpful in preventing bone loss, osteoporosis and fracture. Calcifications are not equivalent to cancer. But they are signs of changes within the breast, and certain patterns of calcifications can be associated with cancer or benign breast disease.

What is a Cyst?

Cysts are harmless accumulations of fluid in the breast (or other tissue or organs). The exact causes of cysts are not known, but cysts are known to change with hormonal variations, either during normal menstrual cycles or from post-menopausal hormone replacement. Contrary to popular belief, caffeine has no proven effect on cysts. Cysts do not become cancer or increase the risk of cancer. Most of the time, cysts may be left alone, but sometimes a physician may drain them with a small needle.

What is Fibroadenoma (FA)?

Fibroadenoma is the most common benign, solid growth in the breasts. Fibroadenoma is round, movable, and firm. Fibroadenoma has no significant risk of becoming cancer and does not put a patient at increased risk of breast cancer.

What is Fibrocystic Breast Change?

Fibrocystic breast change (also called fibrocystic disease) is single or multiple lumps in the breasts. The lumps are often harmless and fairly common. Often the term fibrocystic breast disease refers to normal, dense fibroglandular tissue. Fibrocystic disease is a term that is often misused in breast cancer screening and diagnosis. In fact, there is usually no actual disease. Fibrocystic disease can only be diagnosed after biopsy or needle aspiration of the lumps. Fibrocystic change in most women is common.

My Breasts are Lumpy. Do I Still Need to Examine Them?

Yes. While lumpy breasts or breasts with many masses or cysts can be very difficult to examine, monthly breast self examination (BSE) is still critical. Even if a woman has lumpy breasts, she can learn the usual pattern of lumps and bumps and then point out new or unusual lumps to her doctor. In fact, without knowledgeable direction from a patient, it may be impossible for a physician to differentiate a new mass from stable lumps.

What Can I do to Lower My Risk of Breast Cancer?

There are many breast cancer risk factors that cannot be controlled such as genetics, early menstruation and family history. Other aspects such diet, early child-bearing, and weight can be controlled to help reduce the risk of breast cancer. Click here to learn more about the various risk factors for breast cancer and for information on a new tool to help determine a woman's breast cancer risk.