Introduction

A mammogram is an x-ray examination of the breast. A mammogram is used to detect and diagnose breast disease in women who have breast symptoms (problems such as a lump, pain or nipple discharge) and in women who have no breast complaints (asymptomatic).

Although breasts have been x-rayed for more than 70 years, modern mammography has only existed since 1969 when the first x-ray machines used just for breast imaging were available. Since then, the technology has advanced a great deal, so that today's mammogram is very different even from those of the mid-1980s. The modern technique uses a special machine only for breast x-rays to produce studies that are high quality but have a low radiation dose (usually about 0.1 to 0.2 rad dose per picture). In the past there were concerns about radiation risks; today if there is a risk, it is very small. To put the radiation dose into perspective, a woman who receives radiation as a treatment for breast cancer will receive several thousands rads. If a woman had yearly mammograms beginning at age 40 years and continuing until 90, she will have received 20-40 rads.

A different type of x-ray is used for the breasts than for other parts of the body. This type of x-ray does not penetrate tissue as easily as the x-ray used for routine chest films or x-rays of the arms or legs. For a mammogram, the breast is squeezed between 2 plates to spread the tissue apart and to allow a lower dose of x-ray. Although this may be temporarily uncomfortable, it only lasts for a few seconds and it has to be done this way to produce a good mammogram. The entire procedure for a screening mammogram takes about 20 minutes.

The X-Ray Machine for Mammograms

This procedure produces a black and white image of the breast tissue on a large sheet of film, which is "read" or interpreted by a radiologist. Radiologists are doctors who have special training in diagnosing diseases by examining images of the inside of the body produced using x-rays, sound waves, magnetic fields and other methods. In addition, other doctors who treat breast diseases may also look at the mammogram.

Reading mammograms is difficult because there is a wide range in what is considered normal. A mammogram is like a fingerprint; the appearance of the breast on a mammogram varies a great deal from woman to woman. And, some breast cancers may produce changes in the mammogram that are difficult to recognize. It is extremely helpful for the radiologist to have the films from previous examinations (not just the report) for comparison. This will help the doctor recognize small changes and detect a cancer as early as possible.

Calcifications are tiny mineral deposits within the breast tissue, which look like small white spots on the films. There are two types of calcifications:

• Macrocalcifications
• Microcalcifications

Macrocalcifications are coarse (larger) calcium deposits that are most likely changes in the breasts caused by aging of the breast arteries, old injuries, or inflammations. These deposits are related to noncancerous conditions and do not require a biopsy. Macrocalcifications are found in about half the women over 50, and in 1 of 10 women under 50.

Microcalcifications are tiny specks of calcium in the breast. They may appear alone or in clusters. Microcalcifications seen on a mammogram do not always mean that cancer is present. The shape and layout of microcalcifications help the radiologist judge how likely it is that cancer is present. In some cases, the microcalcifications do not even mean a biopsy is needed. Instead, a doctor may advise you to have a follow-up mammogram within 3 to 6 months. In other cases, the microcalcifications look more suspicious and a biopsy is recommended.

A mass, which may occur with or without calcifications, is another important change seen on mammograms. A mass can be caused by many things, including cysts. A cyst, which is a benign collection of fluid in the breast, cannot be diagnosed by physical exam alone nor can it be diagnosed by mammography alone. To confirm that a mass is really a cyst, either breast ultrasound or aspiration (removal of fluid) with a needle is needed. If a mass is not a cyst, then you may have more imaging tests. As with calcifications, a mass can be caused by benign breast conditions or by breast cancer. Some masses can be watched with periodic mammography while others may need a biopsy. The size, shape, and margins (edges) of the mass help the radiologist to determine the likelihood of cancer. Your prior mammograms may help show that a mass has not changed for many years, indicating a benign condition and help avoid an unnecessary biopsy. Having your prior mammograms available to the radiologist, as discussed above, is very important.

A mammogram cannot prove that an abnormal area is cancer. If a mammogram raises a significant suspicion of cancer, tissue must be removed for examination under the microscope to tell if it is cancer. This can be done with needle biopsy or open surgical biopsy.

Breast cancer takes years to develop. Early in the disease, most breast cancers cause no symptoms. When breast cancer is detected in the localized stage when it hasn’t spread to the lymph nodes, the 5-year survival rate is 97%. If the cancer has spread regionally to underarm (axillary) lymph nodes, the rate drops to 79%. If the cancer has spread (metastasized) to distant organs such as the lungs, bone marrow, liver, or brain, the 5-year survival rate is 23%.

A screening mammogram is an x-ray examination of the breast in a woman who has no breast complaints (asymptomatic). The goal of screening mammography is to find cancer when it is still too small to be felt by her doctor or the woman. Finding small breast cancers early by a screening mammogram greatly improves a woman’s chance for successful treatment.

A screening mammogram usually takes 2 x-ray pictures (views) of each breast. For some patients, more pictures may be needed to include as much breast tissue as possible.

American Cancer Society Recommendations for Early Breast Cancer Detection

Women age 40 and older should have a screening mammogram every year, and should continue to do so for as long as they are in good health.

Women should be told about the benefits, limitations, and potential harms linked with regular screening. Mammograms can miss some cancers. However, mammograms despite its limitations, remains a very effective and valuable tool for decreasing suffering and death from breast cancer.

Mammograms for older women (over age 65) should be based on the individual, her health, and other serious illnesses. Age alone should not be the reason to stop having regular mammograms. As long as a woman is in good health and would be a candidate for treatment, she should continue to be screened with mammography.

Women in their 20s and 30s should have a clinical breast examination (CBE) as part of a periodic (regular) health exam by a health professional preferably every 3 years. After age 40, women should have a breast exam by a health professional every year.

There may be some benefit in having the CBE shortly before the mammogram. The exam should include instruction for the purpose of getting more familiar with your own breast. Women should also be given information about the benefits and limitations of CBE and BSE (breast self-examination). Breast cancer risk is very low for women in their 20s and gradually increases with age. Women should be told to promptly report any new breast symptoms to a health professional.

BSE is an option for women starting in their 20s. Women should be told about the benefits and limitations of BSE. Women should report any breast changes to their health professional right away.

Women who choose to do BSE should have their BSE technique reviewed during their physical exam by a health professional. It is okay for women to choose not to do BSE or not to do it on a regular schedule. However, by doing the exam regularly, you get to know how your breasts normally feel and you can more readily detect any signs or symptoms If a change occurs, such as development of a lump or swelling, skin irritation or dimpling, nipple pain or retraction (turning inward), redness or scaliness of the nipple or breast skin, or a discharge other than breast milk, you should see your health care provider as soon as possible for evaluation. Remember that most of the time, however, these breast changes are not cancer.

Women at increased risk should talk with their doctor about the benefits and limitations of starting mammograms when they are younger, having additional tests, or having more frequent exams. Women should discuss with their doctor what approaches are best for them. Although the evidence currently available does not justify recommending ultrasound or MRI for screening, women at increased risk might benefit from the results.

The American Cancer Society believes the use of mammograms, clinical breast examination, and breast self-examination, according to the recommendations outlined above, offers women the best opportunity for reducing the breast cancer death rate through early detection. This combined approach is clearly better than any one examination. Without question, breast physical examination without mammograms would miss the opportunity to detect many breast cancers that are too small for a woman or her doctor to feel but can be seen on mammograms. Although a mammogram is the most sensitive screening method, a small percentage of breast cancers do not show up on mammograms but can be felt by a woman or her doctors.

The following are useful suggestions for ensuring that you will receive a good quality mammogram

• Ask to see the FDA certificate that is issued to all facilities that meet high professional standards of safety and quality.
• Use a facility that either specializes in mammograms or does many mammograms a day.
• If you are satisfied that the facility is of high quality, continue to go there on a regular basis so that your mammograms can be compared from year to year.
• Bring a list of the places, dates of mammograms, biopsies, or other breast treatments you have had before.
• If you have had mammograms at another facility, you should make every attempt to get those mammograms so that they are available to the radiologist at the current examination.
• On the day of the examination, do not wear deodorant; this can interfere with the mammogram by appearing on the x-ray film as calcium spots.
• If your breasts are tender the week before your period, you should avoid mammograms during this time. The best time for you to have a mammogram is one week after your period.
• You should describe any breast symptoms or problems that you are having to the technologist performing the examination. You should also be prepared to discuss with the mammography technologist any pertinent history: prior surgeries, hormone use, family or personal history of breast cancer. You should also discuss any new findings or problems in your breasts with your doctor or nurse before having a mammogram.
• If you do not hear from your doctor within 10 days, do not assume that your mammogram was normal - call your doctor or the facility.

• Mammogram costs, or a portion of them, are covered by Medicare, Medicaid, and most private health plans. Low-cost mammograms are available in most communities. Call the American Cancer Society at 1-800-ACS-2345 for information about facilities in your area.
• Having a mammogram requires that you undress above the waist. A wrap will be provided by the facility for you to wear.
• A technologist will be present to position your breasts for the mammogram. Most technologists are women. You and the technologist are the only ones present during the mammogram.
• The whole mammogram procedure takes about 20 minutes. The actual breast compression only lasts a few seconds.
• You may feel some discomfort when your breasts are compressed, but you should not feel pain. To help lessen discomfort, don't have a mammogram just before or during your menstrual period.
• All mammogram facilities are now required to send your results to you within 30 days. You will be contacted within 5 working days if there is a problem with the mammogram.
• Only 1 or 2 mammograms out of every 1,000 lead to a diagnosis of cancer. About 10% of women will require more tests. Don't be alarmed if this happens to you. Only 8%-10% of those women will need a biopsy, and 80% of those biopsies will not be cancer.
• If you are a woman and age 40 or over, you should get a mammogram every year. You can schedule the next one while you're there at the facility and/or request a reminder.

A diagnostic mammogram is an x-ray examination of the breast in a woman who either has a breast complaint (for example, a breast mass, nipple discharge, etc.) or has had an abnormality found during a screening mammogram. During a diagnostic mammogram, more pictures will be taken to carefully study the breast condition. In some cases, special images known as cone views with magnification are used to make a small area of altered breast tissue easier to evaluate. Many other types of x-ray pictures can be obtained, depending on the type of problem and its location in the breast. These x-rays are tailored to the patient's needs.

For example, a diagnostic mammogram may show that a lesion (area of abnormal tissue) has a high likelihood of not being cancer (being benign). For these, it is common to ask the woman to return to be rechecked, usually in 4-6 months. On the other hand, a diagnostic mammogram may show that the abnormal area is not worrisome at all and the woman can then return to routine yearly screening.

Finally, the diagnostic work-up may suggest that a biopsy is needed to tell whether or not the lesion is cancer. If your doctor recommends that you have a biopsy, it does not necessarily mean that cancer is present. About 80% of all breast lesions that are biopsied are found to be benign when evaluated under the microscope. If a biopsy is recommended, the woman should discuss the different types of biopsy with her doctor to determine which method of biopsy is best for her.

The American College of Radiology (ACR) has developed a standard way of describing mammogram findings. In this system, the results are given a code (numbered 0 through 5). This system is called the Breast Imaging Reporting and Data System (BIRADS). Having a standard way of reporting mammogram results lets doctors to use a consistent language and ensures better follow up of suspicious findings.

Category 0: Assessment is incomplete and additional imaging evaluation is needed.

A possible abnormality may not be completely seen or defined and will need additional evaluation including the use of spot compression, magnification views, special mammographic views, or ultrasound.

Category 1: Negative

In this case, there is no significant abnormality to report. The breasts are symmetrical without masses, architectural distortion, or suspicious calcifications.

Category 2: Benign (non-cancerous) Finding

This is also a negative mammogram, but the reporting physician chooses to describe a finding known to be benign such as benign calcifications, intramammary lymph nodes, and calcified fibroadenomas. This ensures that other individuals viewing the mammogram will not misinterpret a benign finding as suspicious, and documents the finding to use in future mammogram assessments.

Category 3: Probably Benign Finding - Follow-up in a short time frame is suggested

The findings placed in this category should have a very high probability of being benign. The findings are not expected to change over a period of follow-up. Since it is not proven benign, it is helpful to see if an area of concern changes over time. Follow up with repeat imaging is usually done every 6 months for a year and then every year for 2 years. This will help avoid unnecessary biopsies but allow for findings that are cancers to be detected within a short period of time.

Category 4: Suspicious Abnormality - Biopsy Should Be Considered

Findings do not definitely look like cancer, but have a substantial probability of being malignant. The radiologist has sufficient concern to recommend a biopsy.

Category 5: Highly Suggestive of Malignancy - Appropriate Action Should Be Taken

The findings are characteristic of cancers and have a high probability of malignancy. Biopsy is very strongly recommended.

A ductogram is a test that is sometimes helpful in determining the cause of a nipple discharge. In this x-ray procedure a fine plastic tube is placed into the opening of the duct into the nipple. A small amount of contrast medium is injected, which outlines the shape of the duct on an x-ray image and will show whether there is a mass inside the duct. Ductal lavage, when breast cells are removed by needle from the milk duct(nipple)in the breast, is a procedure aimed at women who have no symptoms of breast cancer, but are at very high risk for breast cancer. The cells are collected to determine the presence of abnormal cells.

Ultrasound, also known as sonography, is an imaging method in which high-frequency sound waves are used to outline a part of the body. High-frequency sound waves are transmitted through the area of the body being studied. The sound wave echoes are picked up and translated by a computer into an image that is displayed on a computer screen. You are not exposed to radiation during this test.

Breast ultrasound is sometimes used to evaluate breast problems that are found during a screening or diagnostic mammogram or on physical exam. Breast ultrasound is not routinely used for screening. Some studies have suggested that ultrasound be added to screening women with dense breast tissue (which is difficult to evaluate by routine mammography). But, use of ultrasound instead of mammography is not recommended because small calcium deposits, which are one of the earliest signs of cancer, are not visible by ultrasound. Ultrasound is useful for evaluating some breast masses and is the only way to tell if a suspicious area is a cyst without placing a needle into it to aspirate fluid. Cysts cannot be accurately diagnosed by physical exam alone. Breast ultrasound may also be used to help doctors precisely guide a biopsy needle into some breast lesions.

Ultrasound has become a valuable tool to use with mammograMS because it is widely available and less expensive than other options. Usually, breast ultrasound is used to target a specific area of concern found by the mammogram. Ultrasound also helps distinguish between cysts and solid masses and between benign and cancerous tumors. However, the effectiveness of an ultrasound test is dependent upon the operator’s level of skill and experience. Ultrasound seems to also raise issues that a mass may be positive for cancer, but in fact is not. This is called a false positive result. The benefit of ultrasound is greatest for women with high breast density (thickness). Although ultrasound is less sensitive than MRI, it has the advantage of being more available and less expensive.

A mammogram cannot prove that an area seen on the films is cancer. If a mammogram raises a suspicion of cancer, a sample of cells or tissue will need to be removed (biopsy) for examination under the microscope by a pathologist to tell if the suspicious area is indeed cancer.

For years, excisional surgical biopsy was a woman’s only option for this procedure. In this type of biopsy, the surgeon makes an incision in the skin of the breast and removes the entire abnormal area (lesion) together with a narrow zone of normal tissue. Today many suspicious breast abnormalities can be diagnosed without surgery by using needle biopsy. There are 2 types of needle biopsies:

• Fine needle aspiration biopsy (FNAB) uses a very thin needle to remove fluid and tiny fragments of tissue.
• Core needle biopsy (CNB) uses a slightly larger needle to remove a piece of tissue about 1/16 inch in diameter and ½ inch long.

If the breast mass is large enough to feel, the doctor can directly guide the needle by touch. But, even if the mass is too small to be felt, FNAB or CNB can still be done using breast imaging methods to guide the needle into the lesion.

For example, ultrasound imaging can be used so that the doctor can see the needle on a screen as it moves toward and into the mass.

Another method, called stereotactic needle biopsy is useful in some cases in which calcifications or a mass can be seen on mammogram but cannot be felt. Based on mammograms taken from 2 angles, computerized equipment maps the exact location of the mass or calcifications and guides the placement of the needle for CNB or, less often, FNAB.

Wire localization is a procedure used to guide a surgical (excisional) breast biopsy of a small lump that is difficult to locate by touch. It can also be useful with areas that look suspicious on the x-ray (due to calcifications, for example) but do not have a distinct lump. After numbing the area with local anesthetic, a hollow needle, thinner than that used for drawing blood, is placed into the breast and x-ray pictures are taken to guide the needle to the suspicious area. A thin wire is inserted through the center of the needle. A small hook at the end of the wire keeps it in place. The hollow needle is then removed. The surgeon uses the wire as a guide to locate the abnormal area to be removed.

One disadvantage of using fine needle and core biopsy methods to biopsy masses found by mammograms (such as microcalcifications) is that they remove only a small sample of tissue. If the biopsy finds cancer, it can be assumed to be accurate. But, if no cancer is found, it may be because the needle missed the target. Until recently, an excisional biopsy with wire localization was the only way to remove all or most of an area of abnormal tissue containing microcalcifications seen on a mammogram but not felt on exam.

Two new devices have been invented that can be guided by imaging methods and can remove more tissue than a core biopsy.

• The Mammotome, also known as vacuum-assisted biopsy, uses suction to draw tissue into an opening in the side of a cylinder inserted into the breast tissue. A rotating knife then cuts the tissue samples from the rest of the breast. This method usually removes about 2 times as much tissue as core biopsies.
• The ABBI method (short for Advanced Breast Biopsy Instrument) uses a rotating circular knife, and a thin wire heated by electrical current to remove a large cylinder of tissue containing the abnormality. The amount of tissue sampled with the ABBI is usually much greater than with the Mammotome.

The US Food and Drug Administration (FDA) has approved both the Mammotome and ABBI instruments to diagnose breast conditions. But, breast specialists still disagree about when each of these instruments should be used to diagnose conditions that cannot be felt, or whether they should be used at all.

The accuracy rates for FNAB, CNB, Mammotome, ABBI, and surgical biopsy are similar. The accuracy of each method depends on the experience of the doctor with that method. This is especially true with methods that remove smaller amounts of tissue (FNA and core needle biopsy) and, therefore, require more accurate placement of the needle. Each type of biopsy has advantages and disadvantages. The choice of which to use depends on each patient's situation and needs. Some of the factors to consider include how suspicious the lesion appears, how large it is, where in the breast it is located, how many lesions are present, other medical problems the patient may have, and her personal preferences. Women are encouraged to discuss the advantages and disadvantages of different biopsy types with their doctors.

Mammograms after Breast-Conserving Treatment: Removal of the entire breast (mastectomy), is one way of treating breast cancers. Most breast cancers can be treated just as effectively by breast- conserving treatment (BCT) without removing the entire breast. Lumpectomy, a type of BCT, is removal of a cancerous lump and a narrow safety zone or margin of benign breast tissue. Lumpectomy is almost always combined with radiation treatment. Chemotherapy is often given. All of these are components of BCT.

A woman who has had BCT will need to continue having mammograms of the affected breast and of the unaffected side. Most radiologists recommend that patients have a mammogram of the treated breast 6 months after the completion of radiation treatment. Radiation and chemotherapy both cause changes in the skin and breast tissues that show up on the mammogram and make the examination more difficult to interpret. These changes usually peak 6 months after the radiation is completed; the mammogram at this time establishes a new baseline for the affected breast for that woman. Future mammograms will be compared to this exam to follow healing and check for recurrence. The next examination is then 6 months later when the woman is due for her yearly mammogram of both breasts. Experts differ on the best follow-up plan from this point on. Some prefer mammography of the treated breast every 6 months for 2-3 years; others suggest that annual mammograms are adequate. Each woman should consult her doctor for the plan that is best for her.

Mammograms after breast reconstruction: Women who have undergone total, modified radical, or radical mastectomy for breast cancer need no further routine mammography of the affected side (or sides, if both breasts are removed). Mammograms are continued for the unaffected breast at standard one-year intervals. This is very important, since women who have had one breast cancer are at higher risk of developing a new cancer of the other breast.

One type of mastectomy that does require follow-up mammography is the subcutaneous mastectomy. In this operation, the woman retains her natural nipples and the tissue just under the skin; enough tissue is left behind to require yearly screening mammography in these patients. Any woman who is not sure what type of mastectomy she has had should ask her doctor.

Women who have had a breast removed by total, modified radical, or radical mastectomy and reconstructed with silicone gel or saline implants do not need routine mammograms. If the patient has had subcutaneous mastectomy (discussed above), annual imaging is still needed.

After mastectomy, some women choose to have a breast reconstructed using tissue from their own body, most often the stomach (abdomen) area. This type of reconstruction is called a TRAM flap reconstruction, which stands for Transverse Rectus Abdominus Myocutaneous flap. A patient who has had complete (not subcutaneous) mastectomy followed by TRAM flap reconstruction needs no further screening mammograms on the affected side. If there is an area of the TRAM flap that is of concern on the physical examination, a diagnostic mammogram may occasionally be obtained. Further imaging with ultrasound or MRI may also be helpful.

Mammograms after Breast Augmentation (enlargement) with Implants: Women who have implants are a special challenge for mammography screening. The x-rays used for imaging the breasts cannot penetrate silicone or saline implants well enough to show the overlying or underlying breast tissue. Therefore, some breast tissue covered up by the implant will not be seen on the mammogram. In order to see as much breast tissue as possible, women with implants have 4 additional films as well as the 4 standard images taken during a screening mammogram. 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 formation of hard scar tissue around the implants (contractures). They are easiest to take in women whose implants are placed underneath (behind) the chest muscle.

Although an implant rupture can sometimes be diagnosed on a mammogram, often the ruptured implant will look normal on a mammogram. Magnetic resonance imaging (MRI) is extremely accurate in detecting implant rupture. MRI is the imaging method of choice to evaluate the implant itself while mammography is still the best test for evaluating breast tissue. See the section on New and Experimental Breast Imaging Methods for more information on MRI.

Very rarely, mammography can cause an implant to rupture so it is important to tell the technician that you have implants. The guidelines for screening mammograms of women with implants are the same as for women without them. The number of pictures taken for each examination, however, is greater.

Mammography is an excellent way to find most breast cancers at their earliest and most curable stage. However, mammograms do not detect all breast cancers. Tremendous research is being done in the field of breast imaging in order to increase the number of cancers found before they can be felt by the patient or her physician, to find cancers even smaller than those detected currently by mammograms, and to improve the accuracy of breast imaging in distinguishing benign breast conditions from breast cancers. New methods being studied include magnetic resonance imaging (MRI), digital mammography, nuclear medicine studies, and computer aided diagnosis.

Magnetic resonance imaging (MRI): MRI uses magnetization and radio waves, instead of x-rays, to produce very detailed, cross-sectional images. The most useful MRI examinations for breast imaging use a contrast material (Gadolinium DTPA) that is injected into a small vein in the arm before or during the examination. This contrast material improves the ability of MRI to clearly show details of breast tissue. It was hoped that MRI would be equal or better than mammograms in diagnosing breast cancer. Although MRI can detect some conditions not seen on the mammogram, it is less accurate than a routine mammogram in determining which of the abnormal areas are cancer and which are not.

MRI or magnetic resonance imaging has become a useful test to use with mammograms and breast ultrasound for diagnosis of breast cancer. A summary of the current research done on use of breast MRI shows an overall sensitivity to breast cancer of 96%. However, MRI is more costly, lacks standard exam techniques and interpretation norms, cannot detect microcalcifications and perhaps has a higher false-positive rate.

As noted earlier, MRI is very useful in detecting rupture of breast implants. Just as x-ray mammogram uses dedicated equipment (x-ray machines designed especially for mammography), breast MRI also requires special equipment. Higher quality images are produced by dedicated breast MRI equipment than by equipment designed for head, chest, or abdominal MRI scanning. However, most hospitals and imaging centers do not have dedicated breast MRI equipment available.

Digital mammograms: Digital mammography is similar to standard mammography in that x-rays are used to produce an image of the breast. The differences are in the way the image is recorded, viewed by the doctor, and stored. Standard mammogram images are recorded on large sheets of photographic film. Digital images are captured electronically and viewed on a computer monitor (like a television screen). They are stored on a computer and their magnification, brightness, or contrast can be changed after the exam is done to help the doctor more clearly see certain areas.

Digital images can be transmitted over phone lines to another location for remote consultation with breast specialists. A digital mammogram is commonly used in stereotactic imaging to guide breast biopsy because it is rapid and reliable. Early studies have shown that a digital mammogram is at least as accurate asx-ray mammograms; additional work with this technique may show digital mammograms are superior.

One recently FDA (Food and Drug Administration)approved technology is full-field digital mammograms (FFDM). FFDM has not been extensively studied, but it does have a lower biopsy rate and a lower sensitivity that is not significantly worse than traditional mammograms. Digital mammograms are not widely available in hospitals around the country.

Early in 2000, the FDA approved a digital mammogram system that can now be used for routine breast cancer screening. While many facilities providing mammogram services do not currently offer the digital option, it is expected to become more widely available in time.

Nuclear medicine studies:

• Techetium sestamibi: For breasts, a compound known as technetium sestamibi has been evaluated to help diagnose breast cancer. This test is manufactured by DuPont under the trade name "Miraluma". In this procedure, a small amount of radioactive substance is injected into an arm vein followed by imaging with a camera that records where radiation has accumulated in the breasts. This procedure cannot distinguish cancer from non-cancerous lesions as accurately as routine mammography. Some radiologists believe it is sometimes useful in evaluating abnormalities of uncertain significance found by regular mammograms. However, studies of the test have yielded varying results. The consensus is that this test is less sensitive than mammography, especially when the tumor is still small and most likely to be curable. For these reasons, the exact role of this test remains uncertain. Research in progress, is aimed at improving the technology and evaluating its use in specific situations such as dense breasts of younger women.

• Positron emission tomography (PET) is a newer type of nuclear medicine study. As in the sestamibi test described above, a tiny amount of radioactive substance is injected into an arm vein. This substance gives off a small amount of radiation that is detected by a special PET scanner to form an image. The most commonly used substance is fluorodeoxyglucose (FDG) that is metabolized (used by cells) in the body like sugar. It goes where the tissue is most active, especially highlighting cancerous tissue. Unlike most other imaging tests that are based on changes tumors cause in the body's structure, PET scanning depends on changes in tissue metabolism. PET is being used to detect metastatic disease (cancer spread) and has been successful in that role. PET scans create an image of the breast (or of biochemical events) after the injection of a very low dose of a radioactive substance such as glucose (sugar). The scan computes the rate at which the tumor is using the sugar. It is not currently used for primary breast cancer detection because it does not reliably detect tumors smaller than 1 cm, but research is being done to improve the accuracy of this test.

Computer-aided diagnosis: Computers can help doctors identify abnormal areas on a mammogram. These instruments convert a mammogram image into a digital signal that is analyzed by the computer. The computer then displays the image on a video screen, with markers pointing to areas it "thinks" the radiologist should check especially closely. The M1000 Image Checker is one such device that has been approved by the US Food and Drug Administration (FDA) for use in reviewing mammograms.

Over the past two decades, computer-aided detection and diagnosis (CAD) has been developed to help radiologists detect suspicious abnormalities on mammograms. This is done most commonly with screen-film mammograms and less often with digital mammograms. Early research results suggest that CAD systems help radiologists diagnose more early stage cancers than mammograms alone.

Early tests have found that it can find some cancers that doctors might have otherwise missed. But, doctors still disagree about how many cancers the device will pick up. Some doctors feel that the device is not as effective as simply having another radiologist review the films, and others are concerned that the device may lead to unnecessary biopsies by falsely identifying benign abnormalities as being suspicious for cancer. Most breast specialists are encouraged by recent progress in computer-aided diagnosis, and look forward to more technical refinements and studies that help to clarify their role in breast cancer detection.

Thermography (or thermal imaging): This is a way of measuring and mapping the heat from the breast with the use of a special camera. A computer looks for “hot spots” or differences in heat then analyzes the images. The theory is that if an area of increased heat is found, it may indicate an increase in blood vessel formation due to cancer. However, studies have not proven this to be an effective screening tool for early diagnosis of breast cancer and it is not a replacement for mammograms. While thermography is approved by the US Food and Drug Administration as safe, it is not approved as a stand alone screening test for breast cancer. It is not a reliable diagnostic test since it can miss some cancers and can give a high false positive rate.

Computed tomography laser mammograms: Computed tomography laser mammography (CTLM) is an imaging test using laser technology to examine different planes of breast tissue and produce a 3D view of the breast. The technique does not use radiation and does not require breast compression. This test is only available in clinical studies and has not been approved for general use by the FDA.

Electrical impedance imaging: Electrical impedance imaging scans the breast for electrical conductivity because breast cancer cells conduct electricity better. This test has received FDA approval to be used as a diagnostic aid to mammography. However, it has not undergone enough clinical testing to be used to recommend in breast cancer screening.

In the United States, mammography is highly regulated. Although mammography using dedicated machines has improved since its introduction in 1969, studies in the mid-1980s showed that quality varied greatly from place to place. In an attempt to educate those working with mammography, improve quality, and lower the dose of radiation, the American College of Radiology (ACR) started the first national Mammography Accreditation Program (MAP) in 1986. This voluntary program raised standards nationwide and led to better mammography at those sites participating in the program.

In 1992, Congress enacted a law to apply similar standards at all mammography facilities. The standards are no longer voluntary and today, the US Food and Drug Administration (FDA) must certify each mammography facility (except those of the Department of Veterans Affairs). In order to be certified, the equipment, personnel, and practice of the facility must be reviewed by an FDA-approved accreditation body and meet the following criteria:

• Each mammogram machine has to be accredited
• Certain personnel must meet strict standards including:

  - Radiologists (the physicians who interpret the mammograms)

  - Radiologic mammography technologists (the individuals who actually position women for the exam and take the mammogram pictures)

  - Medical physicists (professionals who specialize in medical equipment and image production)

• Typical x-rays are reviewed for quality and information on radiation dose, which is required to be very low.

If the facility meets all of the appropriate standards, the FDA gives its certification. These standards are outlined in the Mammography Quality Standards Act (MQSA), which was passed by Congress and has been in effect since 1994. It is unlawful to perform mammograms in the United States without an FDA certificate.

The FDA has a list of all of its certified mammography facilities by state and zip code. This list is available at the FDA's Web site: www.fda.gov/cdrh/mammography/certified.html.

Reporting results: Mammogram clinics are now required to notify women in writing about the results of their mammograms. The Mammography Quality Standards Act, under FDA regulation, was recently changed in response to reports that some women may not have learned soon enough they had suspicious mammograms. Mammogram clinics are continuing to report mammogram results to the woman's doctor, who is responsible for ordering additional tests or treatments. The new amendment to the regulation requires clinics to mail women a separate, easy-to-understand report of their mammogram results within 30 days -- sooner if the mammogram results suggest cancer is present -- so that the woman knows the results even if her doctor has not yet called to inform her.

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Revised 9/30/2003