Introduction

A mammogram is an x-ray exam of the breast. It is used to detect and evaluate breast abnormalities, both in women who have no breast complaints or symptoms and in women who have breast symptoms (problems such as a lump, pain, or nipple discharge). Mammograms are most often used to look for cancer in women who have no symptoms. These are called screening mammograms. Those done in women who have lumps or other symptoms are called diagnostic mammograms.

Although the use of x-rays to examine the breast was first introduced more than 90 years ago, modern mammography has only existed since 1969, when the first dedicated x-ray machines used just for breast imaging became 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 special type of x-ray machine used for the breasts produces lower energy x-rays that do not penetrate tissue as easily as that used for routine chest x-rays or x-rays of the arms or legs, but it does improve the contrast of the image. Modern mammography also results in a significantly lower dose of radiation to the breast compared with the earlier machines.

For a mammogram, the breast is squeezed between 2 plastic plates attached to the mammogram machine, as shown in the picture below. This squeezing or compression is needed to spread the tissue apart. It also ensures that there will be very little movement, that the image is sharper, and that the exam can be done with a lower x-ray dose. Although this compression causes discomfort, it only lasts for a few seconds and is needed to produce a good mammogram. The entire procedure for a mammogram takes about 20 minutes.

The x-ray machine for mammograms

Mammography 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 looking at images of the inside of the body produced by x-rays, sound waves, magnetic fields, or other methods. Other doctors who treat breast diseases may look at the mammogram too.

Reading mammograms is challenging. 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 hard to notice. It is very important that the radiologist has the x-ray films from previous mammograms (not just the report) for comparison. This helps the doctor find small changes and detect a cancer as early as possible. Because getting your older films can be difficult, it is best to find a facility that you are comfortable with and plan to get your regular mammograms there each year. That way, your prior films are easily available.

Screening Mammograms

Breast cancer takes years to develop. Early in the disease, most breast cancers cause no symptoms. When breast cancer is detected at a localized stage (it hasn’t spread to the lymph nodes), the 5-year survival rate is 98%. If the cancer has spread to nearby lymph nodes (regional disease), the rate drops to 84%. If the cancer has spread (metastasized) to distant organs such as the lungs, bone marrow, liver, or brain, the 5-year survival rate is 27%.

A screening mammogram is an x-ray exam of the breast in a woman who has no symptoms. The goal of a screening mammogram is to find cancer when it is still too small to be felt by a woman or her doctor. 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.

• Current evidence supporting mammograms is even stronger than in the past. In particular, recent evidence has confirmed that mammograms offer substantial benefit for women in their 40s. Women can feel confident about the benefits associated with regular mammograms for finding cancer early. However, mammograms also have limitations. A mammogram will miss some cancers, and it sometimes leads to follow up of findings that are not cancer, including biopsies.

• Women should be told about the benefits, limitations, and potential harms associated with regular screening. While mammograms will detect most breast cancers, a small percentage will be missed. Also, sometimes signs on a mammogram that appear abnormal may require a biopsy (the removal of a sample of tissue to see whether cancer cells are present) that will turn out not be breast cancer. In this instance, a woman has undergone a procedure for an abnormality that wasn’t cancer, and she has been through a period of anxiety about the possibility of having breast cancer. However, mammograms, despite their limitations, remain the most effective and valuable tool for decreasing suffering and death from breast cancer.

• There is no fixed age at which women should stop getting mammograms. Mammograms for older women (over age 65) should be based on the woman’s health and whether or not she has 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 have mammograms.

Women in their 20s and 30s should have a clinical breast exam (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.

• CBE is a complement to mammograms and an opportunity for women and their doctor or nurse to discuss changes in their breasts, early detection testing, and factors in the woman’s history that might make her more likely to have breast cancer.

• There may be some benefit in having the CBE shortly before the mammogram because if the examiner discovers a mass, then the mammogram can focus on that area of suspicion. The exam should include instruction for the purpose of helping a woman become familiar with her own breasts. Women should also be given information about the benefits and limitations of CBE and BSE (breast self-exam). 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.

• Research has shown that BSE plays a small role in finding breast cancer compared with finding a breast lump by chance or simply being aware of what is normal for each woman. Some women feel very comfortable doing BSE regularly (usually monthly) which involves a systematic step-by-step approach to examining the look and feel of one’s breasts. Other women are more comfortable simply looking and feeling their breasts in a less systematic approach, such as while showering or getting dressed or doing an occasional thorough exam. Sometimes, women are so concerned about "doing it right" that they become stressed over the technique. Doing BSE regularly is one way for women to know how their breasts normally look and feel and to notice any changes. The goal, with or without BSE, is to report any breast changes to a doctor or nurse 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 a lump or swelling, skin irritation or dimpling, nipple pain or retraction (turning inward), redness or scaliness of the nipple or breast skin, a discharge other than breast milk, or a change in the size of one breast, you should see your doctor or nurse as soon as possible for evaluation. Remember that most of the time these breast changes are not cancer.

Women at high risk (greater than 20% lifetime risk) should get an MRI (magnetic resonance imaging) and a mammogram every year. Women at moderately increased risk (15% to 20% lifetime risk) should talk with their doctors about the benefits and limitations of adding MRI screening to their yearly mammogram. Yearly MRI screening is not recommended for women whose lifetime risk of breast cancer is less than 15%.

• Women at high risk include those who:
  • have a known BRCA1 or BRCA2 gene mutation
  • have a first-degree relative (mother, father, brother, sister, or child) with a BRCA1 or BRCA2 gene mutation, and have not had genetic testing themselves
  • have a lifetime risk of breast cancer of 20%-25% or greater, according to risk assessment tools that are based mainly on family history
  • had radiation therapy to the chest when they were between the ages of 10 and 30 years
  • have a genetic disease such as Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome, or have one of these syndromes in first-degree relatives

• Women at moderately increased risk include those who:
  • have a lifetime risk of breast cancer of 15%-20%, according to risk assessment tools that are based mainly on family history
  • have a personal history of breast cancer, ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), atypical ductal hyperplasia (ADH), or atypical lobular hyperplasia (ALH)
  • have extremely dense breasts or unevenly dense breasts when viewed by mammograms

• If MRI is used, it should be in addition to, not instead of, a screening mammogram. This is because while an MRI is a more sensitive test (it's more likely to detect cancer than a mammogram), it may still miss some cancers that a mammogram would detect.

• For most women at high risk, screening with MRI and mammograms should begin at age 30 years and continue for as long as a woman is in good health. But because the evidence is limited regarding the best age at which to start screening, this decision should be based on shared decision making between patients and their health care providers, taking into account personal circumstances and preferences.

• Several risk assessment tools, with names such as BRCAPRO, the Claus model, and the Tyrer-Cuzick model, are available to help health professionals estimate a woman's breast cancer risk. These tools give approximate, rather than precise, estimates of breast cancer risk based on different combinations of risk factors and different data sets. As a result, they may give different risk estimates for the same woman. Their results should be discussed by a woman and her doctor when being used to decide on whether to start MRI screening.

• It is recommended that women who get screening MRI do so at a facility that can do an MRI-guided breast biopsy at the same time if needed. Otherwise, the woman will have to have a second MRI exam at another facility at the time of biopsy.

• There is no evidence at this time that MRI will be an effective screening tool for women at average risk. While MRI is more sensitive than mammograms, it also has a higher false-positive rate (where the test finds things that turn out to not be cancer), which would result in unneeded biopsies and other tests in a large portion of these women.

The American Cancer Society believes the use of regular mammograms, MRI (in women at high risk), clinical breast exams, and finding and reporting breast changes early, according to the recommendations outlined above, offers women the best chance for reducing the breast cancer death rate through early detection. This combined approach is clearly better than any one test. Without question, breast physical exam without mammograms would miss 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 a sensitive screening method, a small percentage of breast cancers do not show up on mammograms but can be felt by a woman or her doctor. For women at high risk of breast cancer, such as those with BRCA gene mutations or a strong family history, both MRI and mammogram exams of the breast are recommended.

Diagnostic Mammograms

A diagnostic mammogram is an x-ray exam of the breast in a woman who either has a breast complaint (for example, a breast mass, nipple discharge, etc.) or has had something abnormal found during a screening mammogram. During a diagnostic mammogram, more pictures are taken to carefully study the area of concern. In most cases, special images involve magnification to make a small area of suspicious breast tissue easier to evaluate. Many other types of x-ray pictures can be done, depending on the type of problem and its location in the breast.

For example, a diagnostic mammogram may show that an area that appeared to be abnormal actually was quite normal on closer exam, and the woman can then return to routine yearly screening.

It also could show that an area of abnormal tissue has a high likelihood of not being cancer (being benign). For this, it is common to ask the woman to return to be rechecked, usually in 4 to 6 months.

Finally, the diagnostic work-up may suggest that a biopsy is needed to tell whether or not the abnormal area is cancer. If your doctor recommends that you have a biopsy, it does not mean that you have cancer. About 80% of all breast changes that are biopsied are found to be benign (not cancerous) when looked at under the microscope. If a biopsy is needed, you should discuss the different types of biopsy (see below) with your doctor to decide which method of biopsy is best for you.

Tips for Having a Mammogram

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

• If it is not posted in a place you can see it (often near the receptionist’s desk), ask to see the FDA certificate that is issued to all facilities that offer mammography. The FDA requires that all facilities meet high professional standards of safety and quality in order to provide mammography services. Without certification, a facility may not provide mammography.

• Use a facility that either specializes in mammography 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.

• If you are going to a facility for the first time, 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 to bring with you to the new facility (or have them sent there) so that they can be compared to the new ones.

• On the day of the exam, don’t wear deodorant or antiperspirant. Some of these contain substances that can interfere with the reading of the mammogram by appearing on the x-ray film as white spots.

• You may find it more convenient to wear a skirt or pants, so that you’ll only need to remove your blouse for the exam.

• Schedule your mammogram when your breasts are not tender or swollen to help reduce discomfort and to assure a good picture. Try to avoid the week just before your period.

• Always describe any breast symptoms or problems that you are having to the technologist who is doing the mammogram. Be prepared to describe any related medical history such as prior surgeries, hormone use, and any breast cancer that you or a family member has had. Also discuss any new findings or problems in your breasts with your doctor or nurse before having a mammogram.

• Before having any type of imaging test, tell your radiology technologist if you are breastfeeding or if you think you might be pregnant.
• If you do not hear from your doctor within 30 days, do not assume that your mammogram was normal -- call your doctor or the facility.

What to Expect When You Get a Mammogram

• Having a mammogram requires that you undress above the waist. The facility will provide a wrap for you to wear.

• A technologist will position your breasts for the mammogram. Most technologists are women. You and the technologist are the only ones in the room during the mammogram.

• The whole procedure takes about 20 minutes. The actual breast compression only lasts a few seconds.

• You will feel discomfort when your breasts are compressed, and for some women compression can be painful. Try not to schedule a mammogram when your breasts are likely to be tender, as they may be just before or during your period.

• All mammogram facilities are now required to send your results to you within 30 days. Generally, you will be contacted within 5 working days if there is a problem with the mammogram.

• Only 2 to 4 screening mammograms of every 1,000 lead to a diagnosis of cancer. About 10% of women who have a mammogram will require more tests, but most will only need another mammogram. Don't panic if this happens to you. Only 8% to 10% of those women will need a biopsy, and most (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. Or you can ask for a reminder to schedule it as the date gets closer. Some women schedule the next year's mammogram and ask to be reminded of the appointment a few weeks ahead of time.

Help With Mammogram Costs

Medicare, Medicaid, and most private health insurance plans cover mammogram costs, or at least part of them. Low-cost mammograms are available in most communities. Call the American Cancer Society at 1-800-ACS-2345 (1-800-227-2345) for information about facilities in your area. In addition, the National Breast and Cervical Cancer Early Detection Program (NBCCEDP) provides breast and cervical cancer early detection testing to women without health insurance for free or at very little cost. To learn more about this program, please contact the Centers for Disease Control and Prevention (CDC) at 1-888-842-6355 or on the Internet at www.cdc.gov/cancer/nbccedp/.

Regulation of Mammography

In the United States, mammography is highly regulated. Although the quality of mammography 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 Cancer Society approached the American College of Radiology (ACR) and requested that it establish standards and criteria that would help women and doctors find those facilities that provided high quality screening services. In 1986, the ACR started the first national Mammography Accreditation Program (MAP). This voluntary program raised standards nationwide and led to better mammography at those sites that took part in the program.

In 1992, Congress passed 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 staff members must meet strict standards including:

  • radiologists (the doctors who interpret the mammograms)
  • radiologic technologists (those 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 required standards, the FDA gives its certification. These standards are outlined in the Mammography Quality Standards Act (MQSA), which 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: http://www.fda.gov/cdrh/mammography.

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 that 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. A newer part of 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 tell her.

Radiation Exposure From Mammograms

The modern mammography machine produces breast x-rays that are high in image quality but uses a low radiation dose (usually about 0.1 to 0.2 rads per picture). In the past there were concerns about radiation risks. Today if there is a risk, it is very small.

Strict guidelines are in place to ensure that mammography equipment is safe and uses the lowest dose of radiation possible. Many people are concerned about the exposure to x-rays, but the level of radiation in modern mammography does not significantly increase the risk for breast cancer.

To put dose into perspective, if a woman with breast cancer is treated with radiation, she will likely receive a total of around 5,000 rads (a rad is a measure of radiation dose). If she has yearly mammograms beginning at age 40 and continues until she is 90, she will have received 20 to 40 rads. To put it another way, the dose of radiation that you get during a screening mammogram is about the same amount of radiation from your natural surroundings (background radiation) you would average in a 3-month period.

What Does the Doctor Look for on Your Mammogram?

The doctor reading your films will look for several types of changes:

Calcifications are tiny mineral deposits within the breast tissue, which look like small white spots on the films. They may or may not be caused by cancer. There are 2 types of calcifications:

• Macrocalcifications are coarse (larger) calcium deposits that are most likely changes in the breasts caused by aging of the breast arteries, old injuries, or inflammation. These deposits are related to non-cancerous 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 are more a cause for concern, but still usually do not mean that cancer is present. The shape and layout of microcalcifications help the radiologist judge how likely it is that cancer is present. In most instances, the presence of microcalcifications does not mean a biopsy is needed. In other cases, the microcalcifications look more suspicious and a biopsy is needed.

A mass, which may occur with or without calcifications, is another important change seen on mammograms. Masses can be many things, including cysts (non-cancerous, fluid-filled sacs) and non-cancerous solid tumors (such as fibroadenomas), but they could be cancer and usually should be biopsied if they are not cysts.

• A cyst cannot be diagnosed by physical exam alone, nor can it be diagnosed by a mammogram alone. To confirm that a mass is really a cyst, either breast ultrasound or removal of fluid with a thin, hollow needle (aspiration) is needed.

• If a mass is not a simple cyst (that is, if it is at least partly solid), then you may need to have more imaging tests. Some masses can be watched with regular mammograms, while others may need a biopsy. The size, shape, and margins (edges) of the mass help the radiologist to determine whether cancer may be present.

Your prior mammograms may help show that a mass has not changed for many years, which would mean that the mass is likely a benign condition and a biopsy would not be needed. Having your prior mammograms available to the radiologist, as discussed above, is very important.

A mammogram may show something suspicious, but by itself it cannot prove that an abnormal area is cancer. If a mammogram raises a suspicion of cancer, tissue must be removed and looked at under the microscope to tell if it is cancer. This can be done with a needle biopsy or an open surgical biopsy (described below).

Mammogram Reports (BIRADS)

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 6). This system is called the Breast Imaging Reporting and Data System (BIRADS). Having a standard way of reporting mammogram results lets doctors use a consistent language and ensures better follow up of suspicious findings.

Assessment Is Incomplete

Category 0: Additional Imaging Evaluation and/or Comparison to Prior Mammograms Is Needed.

Assessment Is Complete

Category 1: Negative

Category 2: Benign (Non-cancerous) Finding

Category 3: Probably Benign Finding – Follow-up in a Short Time Frame Is Suggested

Category 4: Suspicious Abnormality – Biopsy Should Be Considered

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

Category 6: Known Biopsy-Proven Malignancy – Appropriate Action Should Be Taken

Imaging-Guided Breast Biopsy

A suspicious area in the breast may be found by physical exam, mammogram or another imaging method, or by some combination of these. But regardless of how it was found, cancer can only be confirmed by a biopsy, in which a sample of cells or tissue is removed and looked at under the microscope. For suspicious areas that cannot be felt (and even for some that can), imaging tests may be done to be sure the right area is biopsied. There are several types of biopsies now available.

Surgical Biopsy

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 the surrounding normal tissue (called the margin). It may leave a scar at the incision site.

Wire localization is a procedure used to guide a surgical (excisional) breast biopsy of a small mass that would be hard for the surgeon to locate. 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 (drug to numb the skin), a hollow needle (thinner than those used for drawing blood) is placed into the breast. X-rays are used to guide the needle to the suspicious area. A thin wire is then 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.

Needle Biopsy

Many suspicious breast abnormalities can now be diagnosed without surgery by using needle biopsy. There are 2 types of needle biopsies:

• Fine needle aspiration (FNA) biopsy uses a very thin, hollow 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.

Usually several samples are taken with either of these techniques.

If the breast mass is large enough to feel, the doctor can do a needle biopsy by directly guiding the needle into the lump.

If the mass is too small or too deep within the breast to be felt, biopsies are 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 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, FNA biopsy.

A stereotactic core needle biopsy can sample breast changes felt by the doctor, as well as smaller ones pinpointed by ultrasound or mammogram. Depending on whether the abnormal area can be felt, about 3 to 5 cores are usually removed.

The needle used in core biopsies is larger than that used in FNA. It removes a small cylinder of tissue (about 1/16- to 1/8-inch in diameter and ½-inch long) from a breast abnormality. The biopsy is done with local anesthesia (drugs are used to make the area numb) in an outpatient setting.

Two stereotactic biopsy methods can remove more tissue than a core biopsy. The Mammotome^® is also known as vacuum-assisted biopsy. For this procedure the skin is numbed and a small incision (about ¼-inch) is made. A probe is inserted through the incision into the abnormal area of breast tissue. A cylinder of tissue is suctioned into the probe then a rotating knife within the probe cuts the tissue sample from the rest of the breast. The Mammotome procedure is done as an outpatient. No stitches are needed and there is minimal scarring. This method usually removes about twice as much tissue as core biopsies. The ABBI method (short for Advanced Breast Biopsy Instrument) uses a probe with a rotating circular knife and thin heated electrical wire to remove a large cylinder of abnormal tissue.

In some centers, the biopsy is guided by an MRI, which locates the tumors, plots its coordinates, and aims the stereotactic biopsy device into the tumor.

A biopsy technique known as ATEC now makes it possible to obtain tissue samples during a vacuum-assisted breast biopsy with magnetic resonance imaging (MRI)-assisted guidance. As with other vacuum-assisted biopsies, this method allows many samples to be taken through a single small incision in the skin, using only local anesthesia (numbing of the area). This technique is being studied in women with a personal or family history of breast cancer, those who have undergone previous breast surgery, and women with dense breast tissue who cannot get accurate screenings with tests such as ultrasound or mammograms.

The accuracy rates for the different types of biopsy techniques seem to be similar, although the accuracy of each method depends largely on the doctor's experience with that method. This is especially true with methods that remove smaller amounts of tissue (FNA and core needle biopsy) because these 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 pros and cons of different biopsy types with their doctors, and to have the procedure done by a doctor experienced in the chosen technique.

Mammograms in Special Circumstances

Mammograms in Younger Women

Mammography is a greater challenge in younger women, usually because their breasts are dense and this can hide a tumor. Since most breast cancers occur in older women, this is usually not a problem, and mammography is not recommended for average-risk women under age 40.

In younger women who are at high risk for developing breast cancer (due to a BRCA1 or BRCA2 gene mutation, a strong family history, or other factors), yearly breast MRIs and mammograms are recommended. For most of these women, screening should begin at age 30 years and continue for as long as the woman is in good health. But because the evidence is limited regarding the best age at which to start screening, this decision should be based on shared decision making between patients and their health care providers, taking into account personal circumstances and preferences.

Mammograms After Breast-Conserving Treatment

Removing the entire breast (mastectomy) is one way of treating breast cancers. Most breast cancers can now be treated just as effectively by breast-conserving treatment (BCT), without removing the entire breast. Lumpectomy, one type of BCT, involves removing a cancerous lump and a narrow margin of the surrounding benign breast tissue. Lumpectomy is almost always combined with radiation treatment.

A woman who has had BCT will need to continue having mammograms of the affected breast and her opposite breast.

Most radiologists recommend that patients have a mammogram of the treated breast 6 months after radiation treatment is finished. Radiation and chemotherapy both cause changes in the skin and breast tissues that show up on the mammogram, making it harder to read. 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 exam 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 a mammogram of the treated breast every 6 months for 2 to 3 years; others suggest that yearly mammograms are adequate. Each woman should talk with her doctor about the plan that is best for her.

Mammograms After Mastectomy (Without Breast Reconstruction)

Women who have had total, modified radical, or radical mastectomy for breast cancer need no further routine screening mammograms of the affected side (or sides, if both breasts are removed).

Modified radical mastectomy removes the breast, skin, nipple, areola, and most of the lymph nodes under the arm on the same side, leaving the chest muscles intact.

Partial or segmental mastectomy removes less than the whole breast, taking only the part of the breast where the cancer was found, along with a margin of healthy breast tissue around the tumor.

Radical mastectomy is surgery for breast cancer in which the breast, chest muscles, and all of the lymph nodes under the arm are moved. This surgery is rarely used now, and is reserved mainly for when the cancer has spread to the chest muscles. Mammograms are usually continued for the unaffected breast each year. 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 a follow-up mammogram is the subcutaneous mastectomy. In this operation, the woman keeps her nipple and the tissue just under the skin. Enough breast 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.

Mammograms After Mastectomy (With Breast Reconstruction)

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

After mastectomy, some women choose to have a breast reconstructed using tissue from their own bodies, most often the stomach (abdomen) area. This type of reconstruction is called a TRAM (transverse rectus abdominis myocutaneous) flap reconstruction. 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 exam, a diagnostic mammogram may be obtained. Further imaging with ultrasound or MRI may also be helpful.

Mammograms After Breast 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 breast tissue that is over or under it. 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 extra films (2 on each side) 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 had hard scar tissue form around the implants (contractures). They are easiest to take in women whose implants are placed underneath (behind) the chest muscle.

While the number of pictures taken for each exam is greater, the guidelines for how often women with implants should have screening mammograms are the same as for women without them.

Although a ruptured (burst) implant can sometimes be diagnosed on a mammogram, often a ruptured implant will look normal. Magnetic resonance imaging (MRI), on the other hand, is extremely accurate in detecting implant rupture. MRI is the best imaging method to check the implant itself, while mammography is still the best test for evaluating breast tissue. See the section, "Other Breast Imaging Tests" in this document for more information on MRI.

Very rarely, mammography can cause an implant to rupture, so it is important to tell the technologist if you have implants.

Attempts to Improve Mammography

While mammography is an excellent way to find most breast cancers at their earliest and most curable stage, it does not detect all breast cancers. Newer techniques may help make mammography more accurate.

Digital Mammograms

Digital mammography (also known as full-field digital mammography or FFDM) 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, looked at by the doctor, and stored. Standard mammogram images are recorded on large sheets of photographic film, whereas digital images are captured electronically and viewed on a computer screen. They are stored on a computer, so that their magnification, brightness, or contrast can be changed after the exam is done to help the doctor see certain areas more clearly. Digital images can be transmitted electronically from one location to another for remote consultation with breast specialists. While many centers do not offer the digital option at this time, it is expected to become more widely available in the future.

Because digital mammograms cost more than standard mammograms, studies are now under way to find out which form of mammogram will help more women in the long run. Some studies have found that women who have FFDM have to return less often for extra imaging tests because of questionable areas on the original mammogram. A recent large study from the National Cancer Institute found that FFDM was more accurate in finding cancers in women younger than 50 and in women with dense breast tissue, although the rates of uncertain (inconclusive) results were similar between FFDM and film mammography. It is important to remember that standard film mammography also is effective for these groups of women, and that they should still get their regular mammogram if digital mammography is not available.

Computer-aided Detection and Diagnosis (CAD)

Over the past 2 decades, computer-aided detection and diagnosis (CAD) has been developed to help radiologists find suspicious areas on mammograms. This is done most commonly with screen-film mammograms and less often with digital mammograms.

Computers can help doctors find abnormal areas on a mammogram by acting as a second set of "eyes." For standard mammograms, the film is fed into a machine, which converts the image into a digital signal that is then analyzed by the computer. The technology can also be applied to an image captured with digital mammography. The computer then displays the image on a video screen, with markers pointing to areas it "thinks" the radiologist should check more 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.

Early tests have found that CAD can help 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 a second radiologist review the films. Others are concerned that the device may lead to unnecessary biopsies by falsely identifying benign changes as being suspicious for cancer. Most breast specialists are encouraged by recent progress in computer-aided detection, and look forward to more technical refinements and studies that help to clarify its role in breast cancer detection.

Other Breast Imaging Tests

While mammography is still considered the most useful test for screening and early detection of breast cancer, other imaging tests may be helpful in certain situations.

Magnetic Resonance Imaging (MRI)

For certain women at high risk for breast cancer, screening MRI is recommended along with a yearly mammogram. MRI is not generally recommended as a screening tool by itself, as it may miss some cancers that mammography would detect.

MRI uses magnets and radio waves instead of x-rays to produce very detailed, cross-sectional images of the body. The most useful MRI exams for breast imaging use a contrast material (gadolinium DTPA) that is injected into a small vein in the arm before or during the exam. This improves the ability of the MRI to clearly show breast tissue details.

While MRI is more sensitive in detecting cancers than mammograms, it also has a higher false-positive rate (where the test finds something that turns out not to be cancer), which results in more call-backs and biopsies. This is why it is not recommended as a screening test for women at average risk of breast cancer. It would result in unneeded biopsies and other tests in a large portion of these women.

Just as mammography uses x-ray machines designed especially to image the breasts, breast MRI also requires special equipment. Higher quality images are produced by dedicated breast MRI equipment than by machines designed for head, chest, or abdominal MRI scanning. However, many hospitals and imaging centers do not have dedicated breast MRI equipment available. It is also important that screening MRIs are done at facilities that can do an MRI-guided breast biopsy at the time of the exam if anything abnormal is found. Otherwise, the scan will need to be repeated at another facility at the time of the biopsy.

MRI is also more expensive than mammography. At this time there are concerns about costs of high-quality MRI breast screening services for women at high risk of breast cancer. Most major insurance companies will likely pay for these screening tests if a woman can be shown to be at high risk, but it's not yet clear if all companies will. If you and your doctor decide that you are at 20% to 25% lifetime risk for breast cancer, you may want to contact your health insurance representative. Another concern is that many women live in areas that are not near adequate facilities for MRI breast screening.

In preparing for a breast MRI, you can eat and drink as usual. You will need to remove clothes with metal parts such as zippers, snaps, or buttons, and put on a gown or top. Jewelry, hairpins, safety pins, and anything else made of metal must be removed before entering the MRI room. The technologist will ask if you have any metal in your body, such as surgical clips, staples, pacemakers, artificial joints, metal fragments, tattoos, permanent eyeliner, and so on. Some metal objects will not cause problems, but others might. Tell the staff before the scan if you have any allergies, if you have breast implants, or if you are pregnant or breast-feeding. You may need to have an IV put in for dye or contrast agent to help outline the structures of the breast. For the actual MRI, you will lie on your stomach on a padded platform with spaces for your breasts. You will need to be very still during the test, which takes around 30 to 45 minutes.

Breast Ultrasound

Ultrasound, also known as sonography, is an imaging method in which high-frequency sound waves are used to look inside a part of the body. A handheld instrument placed on the skin transmits the sound waves through the breast. Echoes from the sound waves 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 may be a helpful addition to mammography when screening women with dense breast tissue (which is hard to evaluate with a mammogram), but the use of ultrasound instead of mammograms is not recommended. A large study is currently underway to evaluate the use of breast ultrasound for screening.

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 remove (aspirate) fluid. Cysts cannot be accurately diagnosed by physical exam alone. Breast ultrasound may also be used to help doctors guide a biopsy needle into some breast lesions.

Ultrasound has become a valuable tool to use along with mammograms because it is widely available, non-invasive, and less expensive than other options. However, the effectiveness of an ultrasound test depends on the operator’s level of skill and experience. Although ultrasound is less sensitive than MRI (that is, it detects fewer tumors), it has the advantage of being more available and less expensive.

Ductogram (Galactogram)

A ductogram is a test that is sometimes helpful in determining the cause of a nipple discharge. In this x-ray procedure, a thin plastic tube is placed into the opening of a duct in the nipple. A small amount of contrast material is injected, which outlines the shape of the duct on an x-ray image and shows whether there is a mass inside the duct.

Ductal lavage and nipple aspiration are not imaging tests, but they are mentioned here because of the confusion that sometimes surrounds them.

Ductal lavage is an experimental test developed for women who have no symptoms of breast cancer but are at very high risk for breast cancer. It is not a test to screen for or diagnose breast cancer, but it may help give a more accurate picture of a woman’s risk of developing it.

Ductal lavage can be done in a doctor’s office or an outpatient facility. An anesthetic cream is applied to numb the nipple area. Gentle suction is then used to help draw tiny amounts of fluid from the milk ducts up to the nipple surface. The fluid droplets that appear help locate the milk ducts' natural openings on the surface of the nipple. A tiny tube (called a catheter) is then inserted into a milk duct opening on the nipple. A small amount of anesthetic is infused into the duct to numb the inside. Saline (salt water) is slowly delivered through the catheter to gently "rinse" the duct and collect cells. The ductal fluid is withdrawn through the catheter and placed into a collection vial. The vial is then sent to a lab, where the cells are viewed under a microscope.

Ductal lavage is much more useful as a test of cancer risk rather than as a screening test for cancer. It is not considered appropriate for women who aren’t at high risk for breast cancer. It is not clear whether it will ever be a useful tool. The test has not been shown to detect cancer early, nor have there been any studies to show that this approach prevents the development of breast cancer or death from breast cancer. More studies are needed to better define the usefulness of this test.

Nipple aspiration also looks for abnormal cells from the ducts, but is much simpler, in that nothing is inserted into the breast. The device for nipple aspiration uses small cups that are placed on the woman's breasts. The device warms the breasts, gently compresses them, and applies light suction to bring nipple fluid to the surface of the breast. The nipple fluid is then collected and sent to a lab for analysis. As with ductal lavage, the procedure may be useful as a test of cancer risk but is not appropriate as a screening test for cancer. The test has not been shown to detect cancer early, nor have there been any studies to show that it prevents the development of breast cancer or death from breast cancer.

Newer and Experimental Breast Imaging Methods

Research in the field of breast imaging is continuing in order to:

• increase the number of cancers found before they can be felt by the patient or her doctor 
• find cancers even smaller than those now detected by mammograms 
• improve the ability to distinguish benign breast conditions from breast cancers

These tests all need further study before their usefulness can be determined.

Nuclear Medicine Studies

Nuclear medicine studies (nuclear scans) involve injecting small amounts of slightly radioactive substances into the body and using special cameras to detect where they go. Depending on the substance injected, different types of abnormalities may be detected. Unlike most other imaging tests that are based on changes tumors cause in the body's structure, nuclear medicine scans depend on changes in tissue metabolism.

Technetium Sestamibi Scan (Scintimammography)

A compound known as technetium sestamibi has been studied to help detect breast cancer. This test is marketed under the trade name Miraluma^®. In this procedure, a small amount of the radioactive substance is injected into an arm vein. A special camera then records where radiation builds up in the breasts.

This procedure cannot distinguish cancer from non-cancerous lesions as accurately as routine mammography, and is not used as a screening test. Some radiologists believe it is sometimes useful in looking at suspicious areas found by regular mammograms. However, studies of the test have yielded varying results. The general consensus is that this test is less able to detect cancer 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 unclear. Current research is aimed at improving the technology and evaluating its use in specific situations such as in the dense breasts of younger women.

Positron Emission Tomography (PET)

PET is another type of nuclear medicine study. Like the sestamibi test, 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 in this test is fluorodeoxyglucose (FDG), which is a type of sugar. It goes to places in the body where the cells are most active, especially highlighting cancerous tissue.

PET is being used to detect metastatic disease (cancer spread) and has been successful in that role. The PET scan is not used to screen for breast cancer because it does not reliably detect tumors smaller than 1 cm (about half an inch), but research is being done to improve the accuracy of this test.

Electrical Impedance Imaging (T-Scan)

Electrical impedance imaging scans the breast for electrical conductivity, based on the idea that breast cancer cells conduct electricity better. It involves passing a very small electrical current through the body and detecting it on the skin of the breast with a small probe (similar to an ultrasound probe). The test does not use radiation or require breast compression.

This test has received FDA approval to be used as a diagnostic aid in helping classify tumors detected by mammography. However, it has not undergone enough clinical testing to be used in breast cancer screening.

Thermography (Thermal Imaging)

Thermography is a way of measuring and mapping the heat on the surface of the breast with the use of a special heat-sensing camera. It is based on the idea that the temperature rises in areas with increased blood flow and metabolism, which could signify a tumor.

Thermography has been around for several decades, and some scientists are still attempting to improve the technology for use in breast imaging. However, no study has ever shown that it is an effective screening tool for the early detection of breast cancer. It should not be used as a replacement for mammograms.

Newer versions of this test are better able to determine small temperature differences. They may prove to be more accurate than older versions, and are now under study to find out if they might be useful in finding cancer.

Other Experimental Imaging Tests

Some newer techniques are now being studied for breast imaging.

Optical Imaging

This involves either passing light through the breast or reflecting light off of it and then somehow measuring the light that returns. The technique does not use radiation and does not require breast compression. Optical imaging might be useful at some point for detecting tumors or the blood vessels supplying them.

One example of optical imaging is computed tomography laser mammography (CTLM). This test passes a harmless laser light through the breast tissue and detects large areas of blood vessels that might signify breast tumors. CTLM is being studied for use along with mammography to reduce the number of false positive tests. It has not yet been approved for use by the FDA.

Other experimental techniques now under study include optoacoustic tomography (sending laser light pulses through the breast and detecting the sound waves they cause) and microwave imaging. These techniques are still in the earliest stages of research.

The American Cancer Society is happy to address almost any cancer-related topic. If you have any more questions, please call us at 1-800-ACS-2345 any day, 24 hours a day.

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Revised: 09/26/2007