Breast health

Mammography

Mammography is a type of low-dose x-ray examination that can detect changes in breast tissue that are too small to feel. In fact, mammography plays a central role in the early detection of breast cancer because it can show changes in the breast up to two years before they can be felt during clinical breast examination or breast self-examination.¹

Types of mammography

Mammography is used in the detection and diagnosis of breast disease and can be classified as either screening mammography or diagnostic mammography.

Screening mammography

Screening mammography involves examination of the breast by means of x-rays of women at higher risk of having breast disease. These women are usually without symptoms. Screening mammography typically involves two views of each breast, although in some women, such as those with breast implants, additional pictures may be needed in order to include as much breast tissue as possible.²

Diagnostic mammography

Diagnostic mammography is an x-ray of the breast and is used to diagnose breast disease in women who display breast symptoms or abnormal clinical findings (e.g., breast lumps). In women whose screening mammogram shows abnormal results, a diagnostic mammogram may be recommended in order to determine the cause of the area of concern on the screening exam.³

Preparing for a mammogram

Prior to your mammogram, be sure to report any new findings or problems with your breasts to you your doctor. Your doctor should also be made aware of any prior breast surgeries, hormone use, and family or personal history of breast cancer.

If you do have sensitive breasts, try to schedule your mammogram for that time of the month when your breasts are the least tender, avoiding the week before your period. The best time to schedule a mammogram is one week following your menstrual period.

While many people are concerned about the exposure to x-ray radiation, rest assured that strict guidelines ensure that mammography equipment uses the lowest possible dose of radiation. Nevertheless, always inform your doctor and the x-ray technologist if there is any chance you may be pregnant.

In addition, the American Cancer Society recommends that you:

• Avoid wearing deodorant, talcum powder or lotion under your arms or on your breasts, since these can appear on the x-ray film as calcium spots.
• Discuss any breast symptoms or problems with the technologist performing your mammogram.
• Ask for old mammograms to bring with you to present to the radiologist when you go for your current mammogram. Old mammograms will provide a basis for comparison.
• Ask when your results will be available. Don't go on the assumption that "no news is good news." If you do not hear from your doctor within 10 days of your mammogram, don't assume the results were normal. Call your doctor or the facility at which you had your mammogram to confirm.

Before the mammogram, you'll be asked to remove all jewelry and clothing above the waist. You?ll be given a wrap of loose-fitting material. This wrap or gown opens in the front.

Only you and the technologist will be present during the mammogram. The technologist will explain the procedure to you and answer any questions. If this is your first mammogram, ensure the technologist explains the equipment to you: a mammography unit is a rectangular box that houses an x-ray tube. It's within this x-ray tube that the x-rays are produced. The mammography unit is a dedicated piece of equipment, used exclusively for x-ray examination of the breast. It has special accessories that allow only the breast to be exposed to the x-rays. Attached to the machine are plates which compress the breast and position it so that images can be obtained from different angles.⁴

The technologist will position your breasts between two plates. These flatten the tissue, and while uncomfortable, this is necessary to produce a mammogram. Compression evens out the breast thickness so that all the tissue can be visualized. In addition to reducing x-ray scatter, thereby increasing the sharpness of the picture, compression also spreads out the tissue so that small abnormalities won't be obscured by overlying breast tissue and allows the use of a lower x-ray dose since a thinner amount of breast tissue is being imaged.⁵

Compression causes some discomfort, but should not cause pain. If your breasts are particularly tender, as they may be just before your period, do not get a mammogram. The technologist will increase compression in gradations: be sure to tell the technologist if pain occurs as compression is increased. If discomfort is significant, less compression will be used.

Compression typically lasts only a few seconds, and the entire process for screening mammography should last no longer than 20 minutes. During the mammogram, the breast is exposed to a small dose of radiation to produce an x-ray image of the internal breast tissue. The image produced is the result of some of the x-rays? being absorbed (attenuation) while others pass through the breast to expose either film or a digital image receptor. The exposed film is then placed either in a developing machine or images are digitally stored in a computer.⁶

Interpreting the mammogram

Mammography produces a black and white image of the breast tissue on a large sheet of x-ray film. A radiologist then analyzes the images, looking for the following types of changes:

Calcifications or microcalcifications

Appearing singly or in clusters, calcifications or microcalcifications are tiny mineral deposits within the breast tissue. These appear as small white spots on the mammogram and are a sign of changes within the breast which should be monitored through regular mammography or examined by biopsy. Calcifications are often caused by benign breast conditions and less frequently by breast cancer.⁷

Masses

A mass, which can occur with or without calcifications, can indicate many things, including cysts and fibroadenomas. They may also be indicative of cancer and should be biopsied if they are not fluid-filled cysts.⁸

Cysts

A cyst is a collection of fluid in a small sac in the breast. A cyst may feel like a soft lump in the breast. In order to confirm that a lump or a mass is a cyst, either breast ultrasound or aspiration (removal of the fluid though a needle) is performed. Only rarely are cysts malignant—if a breast ultrasound of the cyst reveals features that suggest cancer, fluid removed from the cyst will be analyzed to determine the presence of malignant cells.⁹

The radiologist will describe any abnormalities found on the mammogram and suggest a likely diagnosis. He or she will dictate a report which will then be sent to your referring physician. The mammography facility will also notify you of the results a few days after the official report goes to your doctor. If, after 10 days, you have not received the results of your mammogram, be sure to call either your doctor of the mammography facility.¹⁰

How effective is mammography?

Mammography cannot prove that an area of abnormal breast tissue is cancer. To confirm whether cancer is present, a breast biopsy must be performed. Breast biopsy is a procedure in which a small amount of breast tissue is removed and examined under a microscope.¹¹

Mammography is an imperfect science, and initial images may not always be enough to determine the existence of a benign or malignant disease. What's more, interpretation of mammograms is further complicated by virtue of the fact that a normal breast can appear different in every woman. The appearance of a mammogram can also be compromised if there is powder, lotion, or salve on the breasts or if you have undergone breast surgery. Because some breast cancers are hard to visualize, your radiologist may want to compare your mammogram to views from previous examinations. If a finding seems suspicious, he or she may recommend additional diagnostic studies, such as biopsy. Even if your mammogram is normal, if you have a breast lump, be sure to have it checked by your doctor.¹²

You should also be aware that breast implants can also interfere with accurate mammogram readings because both silicone and saline are opaque on x-rays. As a result, they can obscure the view of tissues behind them, particularly if the implant has been placed in front of, rather than beneath, the chest muscles. Nevertheless, experienced technologists and radiologists know how to carefully compress the breasts to improve the view without damaging or rupturing the implant. If you have implants, be sure to ask whether the mammography facility uses special techniques designed to accommodate implants. Before your mammogram, ensure the technologist is experienced in performing mammography on patients with breast implants.¹³

Note also that mammography is less effective in younger women because their breasts are usually more dense, which may obscure a tumor. This is not really a concern, since most breast cancer occurs in older women. However, in younger women who have a genetic risk for breast cancer, magnetic resonance imaging (MRI) is now being recommended as one method of screening for women in this situation.¹⁴

What are the risks and benefits of mammography?

The following table outlines the benefits and risks of mammography.

Benefits

Risks

Imaging of the breast improves a doctor's chances of detecting small tumors. When cancers are small, the woman has more treatment options, and a cure is more likely. Use of screening mammography increases the detection of small abnormal tissue growths confined to the milk ducts in the breast. Known as ductal carcinoma in situ, these early tumors can't harm patients if they are removed at this stage and mammography is the only proven method to reliably detect these tumors.

The effective radiation dose from a mammogram is about 0.7 mSv, which is about the same as the average person receives from background radiation in three months. The Federal mammography guidelines require that each unit be checked by a medical physicist each year to ensure that the unit operates correctly. Women should always inform their doctor or x-ray technologist if there is any possibility they are pregnant. Five to 10 percent of screening mammogram results are abnormal and require more testing (more mammograms, fine needle aspiration, ultrasound or biopsy), and most of the follow-up tests confirm that no cancer was present. It is estimated that a woman who has yearly mammograms between ages 40 and 49 would have about a 30 percent chance of having a false-positive mammogram at some point in that decade, and about a 7 to 8 percent chance of having a breast biopsy within the 10-year period. The estimate for false-positive mammograms is about 25 percent for women ages 50 or older.

Source: Mammography. Radiological Society of North America, Inc. (2004)

Should I be concerned?

According to the American Cancer Society, approximately 0.002% of mammograms (only 1 or 2 out of every 1,000) lead to a diagnosis of breast cancer and approximately 10 percent of women will require additional mammograms. Of those, only 8 to 10 percent will need a biopsy, and 80 percent of those biopsies will not be cancer. Be sure to perform breast self-examination (BSE) regularly and to report any abnormalities or changes to your doctor.¹⁵

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1. Mammography. Radiological Society of North America, Inc. (2004)
2. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
3. Mammography. Radiological Society of North America, Inc. (2004)
4. Mammography. Radiological Society of North America, Inc. (2004)
5. Mammography. Radiological Society of North America, Inc. (2004)
6. Mammography. Radiological Society of North America, Inc. (2004)
7. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
8. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
9. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
10. Mammography. Radiological Society of North America, Inc. (2004)
11. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
12. Mammography. Radiological Society of North America, Inc. (2004)
    Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
13. Mammography. Radiological Society of North America, Inc. (2004)
14. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)
15. Can Breast Cancer Be Found Early? American Cancer Society, Inc. (2004)