Causes of Breast Cancer

Lifestyle-related factors

Not having children, or having them later in life

Women who have not had children or who had their first child after age 30 have a slightly higher breast cancer risk. Having many pregnancies and becoming pregnant at an early 

age reduces breast cancer risk. Pregnancy reduces a woman's total number of lifetime menstrual cycles, which may be the reason for this effect.

Recent oral contraceptive use

Studies have found that women using oral contraceptives (birth control pills) have a slightly greater risk of breast cancer than women who have never used them. Over time, this risk seems to go back to normal once the pills are stopped. Women who stopped using oral contraceptives more than 10 years ago do not appear to have any increased breast cancer risk. When thinking about using oral contraceptives, women should discuss their other risk factors for breast cancer with their health care team.

Post-menopausal hormone therapy (PHT)

Post-menopausal hormone therapy, also known as hormone replacement therapy (HRT) and menopausal hormone therapy (MHT), has been used for many years to help relieve symptoms of menopause and to help prevent osteoporosis (thinning of the bones). Earlier studies suggested it might have other health benefits as well, but those benefits have not been found in more recent, better designed studies.

There are 2 main types of PHT. For women who still have a uterus (womb), doctors generally prescribe estrogen and progesterone (known as combined PHT). Because estrogen alone can increase the risk of cancer of the uterus, progesterone is added to help prevent this. For women who've had a hysterectomy (those who no longer have a uterus), estrogen alone can be prescribed. This is commonly known as estrogen replacement therapy (ERT).

Combined PHT: Use of combined post-menopausal hormone therapy increases the risk of getting breast cancer. It may also increase the chances of dying from breast cancer. This increase in risk can be seen with as little as 2 years of use. Large studies have found that there is an increased risk of breast cancer related to the use of combined PHT. Combined PHT also increases the likelihood that the cancer may be found at a more advanced stage, possibly because it reduces the effectiveness of mammograms.

The increased risk from combined PHT appears to apply only to current and recent users. A woman's breast cancer risk seems to return to that of the general population within 5 years of stopping combined PHT.

ERT: The use of estrogen alone after menopause does not appear to increase the risk of developing breast cancer significantly, if at all. But when used long term (for more than 10 years), ERT has been found to increase the risk of ovarian and breast cancer in some studies.

At this time there appear to be few strong reasons to use post-menopausal hormone therapy (combined PHT or ERT), other than possibly for the short-term relief of menopausal symptoms. Along with the increased risk of breast cancer, combined PHT also appears to increase the risk of heart disease, blood clots, and strokes. It does lower the risk of colorectal cancer and osteoporosis, but this must be weighed against the possible harms, and it should be noted that there are other effective ways to prevent osteoporosis. Although ERT does not seem to have much effect on breast cancer risk, it does increase the risk of stroke. The increased risk of hormone replacement therapy is the same for "bioidentical" and "natural" hormones as it is for synthetic hormones.

The decision to use PHT should be made by a woman and her doctor after weighing the possible risks and benefits (including the severity of her menopausal symptoms), and considering her other risk factors for heart disease, breast cancer, and osteoporosis. If a woman and her doctor decide to try PHT for symptoms of menopause, it is usually best to use it at the lowest dose that works for her and for as short a time as possible.

Not breast-feeding

Some studies suggest that breast-feeding may slightly lower breast cancer risk, especially if it is continued for 1� to 2 years. But this has been a difficult area to study, especially in countries such as the United States, where breast-feeding for this long is uncommon.

The explanation for this possible effect may be that breast-feeding reduces a woman's total number of lifetime menstrual cycles (the same as starting menstrual periods at a later age or going through early menopause).

Alcohol

Consumption of alcohol is clearly linked to an increased risk of developing breast cancer. The risk increases with the amount of alcohol consumed. Compared with non-drinkers, women who consume 1 alcoholic drink a day have a very small increase in risk. Those who have 2 to 5 drinks daily have about 1� times the risk of women who drink no alcohol. Excessive alcohol use is also known to increase the risk of developing cancers of the mouth, throat, esophagus, and liver. The American Cancer Society recommends that women limit their alcohol consumption to no more than 1 drink a day.

Being overweight or obese

Being overweight or obese has been found to increase breast cancer risk, especially for women after menopause. Before menopause your ovaries produce most of your estrogen, and fat tissue produces a small amount of estrogen. After menopause (when the ovaries stop making estrogen), most of a woman's estrogen comes from fat tissue. Having more fat tissue after menopause can increase your chance of getting breast cancer by raising estrogen levels.

The connection between weight and breast cancer risk is complex, however. For example, risk appears to be increased for women who gained weight as an adult but may not be increased among those who have been overweight since childhood. Also, excess fat in the waist area may affect risk more than the same amount of fat in the hips and thighs. Researchers believe that fat cells in various parts of the body have subtle differences that may explain this.

The American Cancer Society recommends you maintain a healthy weight throughout your life by balancing your food intake with physical activity and avoiding excessive weight gain.

Lack of physical activity

Evidence is growing that physical activity in the form of exercise reduces breast cancer risk. The main question is how much exercise is needed. In one study from the Women's Health Initiative, as little as 1� to 2� hours per week of brisk walking reduced a woman's risk by 18%. Walking 10 hours a week reduced the risk a little more.

To reduce your risk of breast cancer, the American Cancer Society recommends 45 to 60 minutes of intentional physical activity 5 or more days a week.

Factors with uncertain, controversial, or unproven effect on breast cancer risk

High-fat diets

Studies of fat in the diet have not clearly shown that this is a breast cancer risk factor.

Most studies have found that breast cancer is less common in countries where the typical diet is low in total fat, low in polyunsaturated fat, and low in saturated fat. On the other hand, many studies of women in the United States have not found breast cancer risk to be related to dietary fat intake. Researchers are still not sure how to explain this apparent disagreement. Studies comparing diet and breast cancer risk in different countries are complicated by other differences (such as activity level, intake of other nutrients, and genetic factors) that might also alter breast cancer risk.

More research is needed to better understand the effect of the types of fat eaten on breast cancer risk. But it is clear that calories do count, and fat is a major source of these. High-fat diets can lead to being overweight or obese, which is a breast cancer risk factor. A diet high in fat has also been shown to influence the risk of developing several other types of cancer, and intake of certain types of fat is clearly related to heart disease risk.

The American Cancer Society recommends eating a healthy diet with an emphasis on plant sources. This includes eating 5 or more servings of vegetables and fruits each day, choosing whole grains over those that are processed (refined), and limiting consumption of processed and red meats.

Antiperspirants

Internet e-mail rumors have suggested that chemicals in underarm antiperspirants are absorbed through the skin, interfere with lymph circulation, and cause toxins to build up in the breast, eventually leading to breast cancer. There is very little laboratory or population-based evidence to support this rumor.

One small study has found trace levels of parabens (used as preservatives in antiperspirants and other products), which have weak estrogen-like properties, in a small sample of breast cancer tumors. However, the study did not look at whether parabens caused the tumors. This was a preliminary finding, and more research is needed to determine what effect, if any, parabens may have on breast cancer risk. On the other hand, a large population-based study found no increase in breast cancer in women who used underarm antiperspirants and/or shaved their underarms.

Bras

Internet e-mail rumors and at least one book have suggested that bras cause breast cancer by obstructing lymph flow. There is no good scientific or clinical basis for this claim. Women who do not wear bras regularly are more likely to be thinner, which would probably contribute to any perceived difference in risk.

Induced abortion

Several studies have provided very strong data that neither induced abortions nor spontaneous abortions (miscarriages) have an overall effect on the risk of breast cancer. For more detailed information, see the separate American Cancer Society document, Is Having an Abortion Linked to Breast Cancer?

Breast implants

Several studies have found that breast implants do not increase breast cancer risk, although silicone breast implants can cause scar tissue to form in the breast. Implants make it harder to see breast tissue on standard mammograms, but additional x-ray pictures called implant displacement views can be used to examine the breast tissue more completely.

Chemicals in the environment

A great deal of research has been reported and more is being done to understand possible environmental influences on breast cancer risk.

Of special interest are compounds in the environment that have been found in lab studies to have estrogen-like properties, which could in theory affect breast cancer risk. For example, substances found in some plastics, certain cosmetics and personal care products, pesticides, and PCBs (polychlorinated biphenyls) seem to have such properties.

Although this issue understandably invokes a great deal of public concern, at this time research does not show a clear link between breast cancer risk and exposure to these substances. Unfortunately, studying such effects in humans is difficult. More research is needed to better define the possible health effects of these and similar substances.

Tobacco smoke

Most studies have found no link between cigarette smoking and breast cancer. Although some studies have suggested smoking increases the risk of breast cancer, this remains controversial.

An active focus of research is whether secondhand smoke increases the risk of breast cancer. Both mainstream and secondhand smoke contain chemicals that, in high concentrations, cause breast cancer in rodents. Chemicals in tobacco smoke reach breast tissue and are found in breast milk.

The evidence on secondhand smoke and breast cancer risk in human studies is controversial, at least in part because smokers have not been shown to be at increased risk. One possible explanation for this is that tobacco smoke may have different effects on breast cancer risk in smokers compared to those who are just exposed to secondhand smoke.

A report from the California Environmental Protection Agency in 2005 concluded that the evidence about secondhand smoke and breast cancer is "consistent with a causal association" in younger, mainly pre-menopausal women. The 2006 US Surgeon General's report, The Health Consequences of Involuntary Exposure to Tobacco Smoke, concluded that there is "suggestive but not sufficient" evidence of a link at this point. In any case, this possible link to breast cancer is yet another reason to avoid secondhand smoke.

Night work

Several studies have suggested that women who work at night, such as nurses on night shift, may have an increased risk of developing breast cancer. This is a fairly recent finding, and more studies are looking at this issue. Some researchers think the effect may be due to changes in levels of melatonin, a hormone whose production is affected by the body's exposure to light, but other hormones are also being studied.

American Cancer Society recommendations for early breast cancer detection in women without breast symptoms

Women age 40 and older should have a 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 can miss some cancers, and it may lead to follow up of findings that are not cancer.

• Women should be told about the benefits and limitations linked with yearly mammograms. But despite their limitations, mammograms are still a very effective and valuable tool for decreasing suffering and death from breast cancer.

• Mammograms should be continued regardless of a woman's age, as long as she does not have serious, chronic health problems such as congestive heart failure, end-stage renal disease, chronic obstructive pulmonary disease, and moderate to severe dementia. Age alone should not be the reason to stop having regular mammograms. Women with serious health problems or short life expectancies should discuss with their doctors whether to continue having 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. Starting at age 40, women should have a CBE by a health professional every year.

• CBE is done along with mammograms and offers a chance 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. The exam should include instruction for the purpose of getting more familiar with your own breasts. Women should also be given information about the benefits and limitations of CBE and breast self-examination (BSE). The chance of breast cancer occurring 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.

Breast self-examination (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 after their period) which involves a systematic step-by-step approach to examining the look and feel of one's breasts. Other women are more comfortable simply 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 use a step-by-step approach to 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 such as once every month. However, by doing the exam regularly, you get to know how your breasts normally look and feel and you can more readily find any changes. 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 (such as staining of your sheets or bra), you should see your health care professional as soon as possible for evaluation. Remember that most of the time, however, these breast changes are not cancer.

Women at high risk (greater than 20% lifetime risk) should get an MRI 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 (parent, 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% to 25% or greater, according to risk assessment tools that are based mainly on family history (see below)

• had radiation therapy to the chest when they were between the ages of 10 and 30 years

• have 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% to 20%, according to risk assessment tools that are based mainly on family history (see below)

• 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 although 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 the Gail model, 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 whether to start MRI screening.

It is recommended that women who get a 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 when she has the biopsy.

There is no evidence right now 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 (it is more likely to find something that turns out not to be cancer). This would lead to unneeded biopsies and other tests in many of the women screened.

The American Cancer Society believes the use of 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 to reduce their risk of dying from breast cancer. This approach is clearly better than any one exam or test alone. Without question, a physical exam of the breast without a mammogram 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. Mammograms are a sensitive screening method, but a small percentage of breast cancers do not show up on mammograms but can be felt by a woman or her doctors. 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.

Mammograms

A mammogram is an x-ray of the breast. A diagnostic mammogram is used to diagnose breast disease in women who have breast symptoms or an abnormal result on a screening mammogram. Screening mammograms are used to look for breast disease in women who are asymptomatic; that is, those who appear to have no breast problems. Screening mammograms usually take 2 views (x-ray pictures taken from different angles) of each breast. Women who are breast-feeding can still get mammograms, although these are probably not quite as accurate because the breast tissue tends to be dense.

For some women, such as those with breast implants (for augmentation or as reconstruction after mastectomy), additional pictures may be needed to include as much breast tissue as possible. Breast implants make it harder to see breast tissue on standard mammograms, but additional x-ray pictures with implant displacement and compression views can be used to more completely examine the breast tissue. If you have implants, it is important that you have your mammograms done by someone skilled in the techniques used for women with implants.

Although breast x-rays have been performed for more than 70 years, modern mammography has only existed since 1969. That was the first year x-ray units dedicated to breast imaging were available. Modern mammogram equipment designed for breast x-rays uses very low levels of radiation, usually about a 0.1 to 0.2 rad dose per x-ray (a rad is a measure of radiation dose).

Strict guidelines ensure that mammogram 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 used in modern mammograms does not significantly increase the risk for breast cancer.

To put dose into perspective, a woman who receives radiation as a treatment for breast cancer will receive several thousand rads. If she had yearly mammograms beginning at age 40 and continuing until she was 90, she will have received 20 to 40 rads. As another example, flying from New York to California on a commercial jet exposes a woman to roughly the same amount of radiation as one mammogram.

For a mammogram, the breast is compressed between 2 plates to flatten and spread the tissue. Although this may be uncomfortable for a moment, it is necessary to produce a good, readable mammogram. The compression only lasts a few seconds. The entire procedure for a screening mammogram takes about 20 minutes.

The x-ray machine for mammography

The procedure produces a black and white image of the breast tissue either on a large sheet of film or as a digital computer image that is "read," or interpreted, by a radiologist (a doctor trained to interpret images from x-rays, ultrasound, magnetic resonance imaging, and related tests.)

What the doctor looks for on your mammogram

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

Calcifications are tiny mineral deposits within the breast tissue that appear as small white spots on the films. They may or may not be caused by cancer. Calcifications are divided into 2 types:

• Macrocalcifications are coarse (larger) calcium deposits that most likely represent degenerative changes in the breasts, such as aging of the breast arteries, old injuries, or inflammation. These deposits are associated with benign (non-cancerous) conditions and do not require a biopsy. Macrocalcifications are found in about half the women over the age of 50, and in about 1 in 10 women younger than 50.

• Microcalcifications are tiny specks of calcium in the breast. They may appear alone or in clusters. Microcalcifications seen on a mammogram are of more concern, but 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 most instances, the presence of microcalcifications does not mean a biopsy is needed. If the microcalcifications look suspicious for cancer, a biopsy will be done.

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). Masses that are not cysts usually need to be biopsied.

• A cyst and a tumor can feel alike on a physical exam. They can also look the same on a mammogram. To confirm that a mass is really a cyst, a breast ultrasound is often done. Another option is to remove (aspirate) the fluid from the cyst with a thin, hollow needle.

• 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 periodic mammograms, while others may need a biopsy. The size, shape, and margins (edges) of the mass help the radiologist to determine if cancer may be present.

Having your previous mammograms available for the radiologist is very important. They can be helpful to show that a mass or calcification has not changed for many years. This would mean that it is probably a benign condition and a biopsy is not needed.

Limitations of mammograms

A mammogram cannot prove that an abnormal area is cancer. To confirm whether cancer is present, a small amount of tissue must be removed and looked at under a microscope. This procedure is called a biopsy. For more information, see the separate American Cancer Society document, For Women Facing a Breast Biopsy.

You should also be aware that mammograms are done to find cancers that can't be felt.. If you have a breast lump, you should have it checked by your doctor, who may recommend a biopsy even if your mammogram result is normal.

For some women, such as those with breast implants, additional pictures may be needed. Breast implants make it harder to see breast tissue on standard mammograms, but additional x-ray pictures with implant displacement and compression views can be used to more completely examine the breast tissue.

Mammograms are not perfect at finding breast cancer. They do not work as well in younger women, usually because their breasts are dense and can hide a tumor. This may also be true for pregnant women and women who are breast-feeding. Since most breast cancers occur in older women, this is usually not a major concern.

However, this can be a problem for young women who are at high risk for breast cancer (due to gene mutations, a strong family history of breast cancer, or other factors) because they often develop breast cancer at a younger age. For this reason, the American Cancer Society now recommends MRI scans in addition to mammograms for screening in these women. (MRI scans are described below.) For more information, also see the separate American Cancer Society document, Mammograms and Other Breast Imaging Procedures.

Tips for having a mammogram

The following are useful suggestions for making sure that you receive a quality mammogram:

• If it is not posted in a place you can see it 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 be a provider of mammography services. A facility may not provide mammography without certification.

• 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.

• Try to schedule your mammogram at a time of the month when your breasts are not tender or swollen to help reduce discomfort and assure a good picture. Try to avoid the week right before your period.

• 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 easier 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 ensure 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 medical history that could affect your breast cancer risk -- such as prior surgery, hormone use, or family or personal history of breast cancer. 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 result 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 give you a wrap to wear.

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

• To get a high-quality mammogram picture, it is necessary to flatten the breast slightly. The technologist places the breast on the mammogram machine's lower plate, which is made of metal and has a drawer to hold the x-ray film or the camera to produce a digital image. The upper plate, made of plastic, is lowered to compress the breast for a few seconds while the picture is taken.

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

• You may feel some 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, and most will only need an additional 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.

For more information on mammograms and other imaging tests for early detection and diagnosis of breast diseases, refer to the American Cancer Society document, Mammograms and Other Breast Imaging Procedures.

Signs and symptoms of breast cancer

Although widespread use of screening mammograms has increased the number of breast cancers found before they cause any symptoms, some breast cancers are not found by mammograms, either because the test was not done or because even under ideal conditions mammograms do not find every breast cancer.

The most common sign of breast cancer is a new lump or mass. A mass that is painless, hard, and has irregular edges is more likely to be cancerous, but breast cancers can be tender, soft, or rounded. For this reason, it is important that any new mass, lump, or breast change is checked by a health care professional with experience in diagnosing breast diseases.

Other possible signs of breast cancer include:

• swelling of all or part of a breast (even if no distinct lump is felt)
• skin irritation or dimpling
• breast or nipple pain
• nipple retraction (turning inward)
• redness, scaliness, or thickening of the nipple or breast skin
• a nipple discharge other than breast milk

Sometimes a breast cancer can spread to underarm lymph nodes and cause a lump or swelling there, even before the original tumor in the breast tissue is large enough to be felt. Swollen lymph nodes should also be reported to your doctor.

Clinical breast exam

A clinical breast exam (CBE) is an examination of your breasts by a health professional, such as a doctor, nurse practitioner, nurse, or physician assistant. For this exam, you undress from the waist up. The health professional will first look at your breasts for abnormalities in size or shape, or changes in the skin of the breasts or nipple. Then, using the pads of the fingers, the examiner will gently feel (palpate) your breasts.

Special attention will be given to the shape and texture of the breasts, location of any lumps, and whether such lumps are attached to the skin or to deeper tissues. The area under both arms will also be examined.

The CBE is a good time for women who don't know how to examine their breasts to learn the right way to do it from their health care professionals. Ask your doctor or nurse to teach you and watch your technique.

Breast awareness and self-exam

Beginning in their 20s, women should be told about the benefits and limitations of breast self-exam (BSE). Women should be aware of how their breasts normally look and feel and report any new breast changes to a health professional as soon as they are found. Finding a breast change does not necessarily mean there is a cancer.

A woman can notice changes by knowing how her breasts normally look and feel and feeling her breasts for changes (breast awareness), or by choosing to use a step-by-step approach and using a specific schedule to examine her breasts.

Women with breast implants can do BSE. It may be useful to have the surgeon help identify the edges of the implant so that you know what you are feeling. There is some thought that the implants push out the breast tissue and may make it easier to examine. Women who are pregnant or breast-feeding can also choose to examine their breasts regularly.

If you choose to do BSE, the following information provides a step-by-step approach for the exam. The best time for a woman to examine her breasts is when the breasts are not tender or swollen. Women who examine their breasts should have their technique reviewed during their periodic health exams by their health care professional.

It is acceptable for women to choose not to do BSE or to do BSE occasionally. Women who choose not to do BSE should still know how their breasts normally look and feel and report any changes to their doctor right away.

How to examine your breasts

Lie down on your back and place your right arm behind your head. The exam is done while lying down, not standing up. This is because when lying down the breast tissue spreads evenly over the chest wall and is as thin as possible, making it much easier to feel all the breast tissue.

Use the finger pads of the 3 middle fingers on your left hand to feel for lumps in the right breast. Use overlapping dime-sized circular motions of the finger pads to feel the breast tissue.

Use 3 different levels of pressure to feel all the breast tissue. Light pressure is needed to feel the tissue closest to the skin; medium pressure to feel a little deeper; and firm pressure to feel the tissue closest to the chest and ribs. It is normal to feel a firm ridge in the lower curve of each breast, but, you should tell your doctor if you feel anything else out of the ordinary. If you're not sure how hard to press, talk with your doctor or nurse. Use each pressure level to feel the breast tissue before moving on to the next spot.

Move around the breast in an up and down pattern starting at an imaginary line drawn straight down your side from the underarm and moving across the breast to the middle of the chest bone (sternum or breastbone). Be sure to check the entire breast area going down until you feel only ribs and up to the neck or collar bone (clavicle).

There is some evidence to suggest that the up-and-down pattern (sometimes called the vertical pattern) is the most effective pattern for covering the entire breast without missing any breast tissue.

Repeat the exam on your left breast, putting your left arm behind your head and using the finger pads of your right hand to do the exam.

While standing in front of a mirror with your hands pressing firmly down on your hips, look at your breasts for any changes of size, shape, contour, or dimpling, or redness or scaliness of the nipple or breast skin. (The pressing down on the hips position contracts the chest wall muscles and enhances any breast changes.)

Examine each underarm while sitting up or standing and with your arm only slightly raised so you can easily feel in this area. Raising your arm straight up tightens the tissue in this area and makes it harder to examine.

This procedure for doing breast self-exam is different from previous recommendations. These changes represent an extensive review of the medical literature and input from an expert advisory group. There is evidence that this position (lying down), the area felt, pattern of coverage of the breast, and use of different amounts of pressure increase a woman's ability to find abnormal areas.

Newer technologies for breast cancer screening

Mammography is the current standard test for breast cancer screening. MRI is also recommended along with mammograms for some women at high risk for breast cancer. Other tests, such as ultrasound, are now being studied as well.

Magnetic resonance imaging

For certain women at high risk for breast cancer, screening magnetic resonance imaging (MRI) is recommended along with a yearly mammogram. MRI is not generally recommended as a screening tool by itself, because although it is a sensitive test, it may still miss some cancers that mammograms would detect. MRI may also be used in other situations, such as to better examine suspicious areas found by a mammogram. MRI can also be used in women who have already been diagnosed with breast cancer to better determine the actual size of the cancer and to look for any other cancers in the breast.

MRI scans use 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) 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.

MRI scans can take a long time -- often up to an hour. You have to lie inside a narrow tube, which is confining and may upset people with claustrophobia (a fear of enclosed spaces). The machine makes loud buzzing and clicking noises that you may find disturbing. Some places provide headphones with music to block this noise out.

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

Just as mammography uses x-ray machines that are specially designed to image the breasts, breast MRI also requires special equipment. Breast MRI machines produce higher quality images than MRI 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 important that screening MRIs are done at facilities that can perform an MRI-guided breast biopsy. Otherwise, the entire scan will need to be repeated at another facility when the biopsy is done.

MRI is more expensive than mammography. 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. At this time there are concerns about costs of and limited access to high-quality MRI breast screening services for women at high risk of breast cancer.

Breast ultrasound

Ultrasound, also known as sonography, is an imaging method in which sound waves are used to look inside a part of the body. For this test, a small, microphone-like instrument called a transducer is placed on the skin (which is often first lubricated with ultrasound gel). It emits sound waves and picks up the echoes as they bounce off body tissues. The echoes are converted by a computer into a black and white image that is displayed on a computer screen. This test is painless and does not expose you to radiation.

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 for breast cancer screening is not recommended.

Ultrasound is useful for evaluating some breast masses and is the only way to tell if a suspicious area is a cyst (fluid-filled sac) without placing a needle into it to aspirate (pull out) 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

This test, also called a galactogram, is sometimes helpful in determining the cause of nipple discharge. Most nipple discharges or secretions are not cancer. In general, if the secretion appears milky or clear green, cancer is very unlikely. If the discharge is red or red-brown, suggesting that it contains blood, it might possibly be caused by cancer, although an injury, infection, or benign tumors are more likely causes.

In this test a very thin plastic tube is placed into the opening of the duct at the nipple. A small amount of contrast material is injected that outlines the shape of the duct on an x-ray image and shows if there is a mass inside the duct.

Digital mammograms

A digital mammogram (also known as a full-field digital mammogram or FFDM) is like a standard mammogram in that x-rays are used to produce an image of your breast. The differences are in the way the image is recorded, viewed by the doctor, and stored. Standard mammograms are recorded on large sheets of photographic film. Digital mammograms are recorded and stored on a computer. After the exam, the doctor can view them on a computer screen and adjust the image size, brightness, or contrast to see certain areas more clearly. Digital images can also be sent electronically to another site for a remote consult 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 determine which form of mammogram will benefit more women in the long run. Some studies have found that women who have FFDM have to return less often for additional imaging tests because of inconclusive areas on the original mammogram. A recent large study 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 inconclusive results were similar between FFDM and film mammograms. It is important to remember that a standard film mammogram also is effective for these groups of women, and that they should not miss their regular mammogram if digital mammography is not available.

Computer-aided detection and diagnosis

Over the past 2 decades, computer-aided detection and diagnosis (CAD) has been developed to help radiologists detect suspicious changes on mammograms. This can be done with standard film mammograms or with digital mammograms.

Computers can help doctors identify 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. Alternatively, the technology can be applied to a digital mammogram. The computer then displays the image on a video screen, with markers pointing to areas it "thinks" the radiologist should check especially closely.

It's not yet clear how useful CAD is. Some doctors find it helpful, but a recent large study found it did not significantly improve the accuracy of breast cancer detection. It did, however, increase the number of women who needed to have breast biopsies. Further research of this approach is needed.

Scintimammography (molecular breast imaging)

In scintimammography, a slightly radioactive tracer called technetium sestamibi is injected into a vein. The tracer attaches to breast cancer cells and is detected by a special camera.

This is a newer technique that most doctors still consider be experimental. Some radiologists believe it is sometimes useful in looking at suspicious areas found by regular mammograms, but its exact role 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. Some early studies have suggested that it may be about as accurate as more expensive MRI scans.

Tomosynthesis (3D mammography)

This technology is basically an extension of a digital mammogram. For this test, a woman lies face down on a table with a hole for the breast to hang through, and a machine takes x-rays as it rotates around the breast. Tomosynthesis allows the breast to be seen as many thin slices, which can be combined into a 3-dimensional picture. It may allow doctors to detect smaller lesions or ones that would otherwise be hidden with standard mammograms. This technology is still considered experimental and is not yet commercially available.

Other tests

These tests may be done for the purposes of research, but they have not yet been found to be helpful in diagnosing breast cancer in most women.

Nipple discharge exam

If you are having nipple discharge, some of the fluid may be collected and looked at under a microscope to see if any cancer cells are in it. But even when no cancer cells are found in a nipple discharge, it is not possible to say for certain that a breast cancer is not there. If a patient has a suspicious mass, a biopsy of the mass is necessary, even if the nipple discharge does not contain cancer cells.

Ductal lavage and nipple aspiration

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.

For this test, gentle suction is used to help draw tiny amounts of fluid from the milk ducts up to the nipple surface, which helps locate the milk ducts' natural openings on the surface of the nipple. A tiny tube is then inserted into a duct opening. Saline (salt water) is slowly infused into the tube to gently rinse the duct and collect cells. The fluid is then withdrawn through the tube and 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. More studies are needed to better define the usefulness of this test.

Nipple aspiration also looks for abnormal cells from the ducts. 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.

Talk to your doctor

If you think you are at higher risk for developing breast cancer, talk to your doctor about what is known about these tests and their potential benefits, limitations, and harms. Then decide together what is best for you.

For more information on imaging tests for early detection and diagnosis of breast diseases, refer to the separate American Cancer Society document, Mammograms and Other Breast Imaging Procedures.

Paying for breast cancer screening

This section provides a brief overview of laws assuring coverage for private health plans, Medicaid, and Medicare coverage of early detection services for breast cancer screening.

State efforts to ensure private health insurance coverage of mammography

Many states require that private insurance companies, Medicaid, and public employee health plans provide coverage and reimbursement for specific health services and procedures. The American Cancer Society (ACS) supports these kinds of patient protections, particularly when it comes to evidence-based cancer prevention, early detection, and treatment services.

The only state without a law ensuring that private health plans cover or offer coverage for screening mammograms is Utah (see table below). Of the remaining 49 states that have enacted either assured benefits or ensured offerings for mammography coverage, many states do not conform to ACS guidelines and are either more or less "generous" than ACS recommendations. Some states like Rhode Island, however, specifically state in their legislative language that mammography screening should be covered according to the ACS guidelines.

State Mammography Screening Coverage Laws

Sources: Health Policy Tracking Service, " Mandated Benefits: Breast Cancer Screening Coverage Requirements," 4/01/04; CDC Division of Cancer Prevention and Control "State Laws Relating to Breast Cancer: Legislative Summary, January 1949 to May 2000."
Health Policy Tracking Service, "Overview: Health Insurance Access and Oversight," 6/20/05
Netscan's Health Policy Tracking Service Health Insurance Snapshot, 8/8/05
Netscan's Health Policy Tracking Service, "Mandated Benefits: An Overview of 2006 Activity," 4/3/06

Updated 9/14/06, ACS National Government Relations Department

Other state efforts and self-insured plans

Other types of health coverage also provide screening mammograms. Public employee health plans are governed by state regulation and legislation, and many cover screening mammograms. Self-insured plans are not regulated at the state level, which means women in these plans do not necessarily get screening mammogram benefits, even if there are laws in the state to cover such benefits. Self-insured plans are typically large employers. Women who have self-insured-based health insurance should check with their health plans to see what breast cancer early detection services are covered.

Medicaid

All state Medicaid programs plus the District of Columbia cover screening mammograms. This coverage may or may not conform to American Cancer Society guidelines. State Medicaid offices should be able to provide screening coverage information to interested individuals. The Medicaid programs are governed by state legislation and regulation, so assured coverage is not always apparent in legislative bills.

In addition, all 50 states plus the District of Columbia have opted to provide Medicaid coverage for all women diagnosed with breast cancer through the Centers for Disease Control and Prevention's (CDC's) National Breast and Cervical Cancer Early Detection Program (see the next section), so that they may receive cancer treatment. This option allows states to receive significant matching funds from the federal government. States vary in the age, income and other requirements that women must meet in order to qualify for treatment through the Medicaid program. (All 50 states, 4 U.S. territories, the District of Columbia, and 13 American Indian/Alaska Native organizations participate in the National Breast and Cervical Cancer Early Detection Program.)

National Breast and Cervical Cancer Early Detection Program

States are making breast cancer screening more available to medically underserved women through the National Breast and Cervical Cancer Early Detection Program (NBCCEDP). This program provides breast and cervical cancer screening to low-income, uninsured, and underserved women for free or at very low cost. The NBCCEDP attempts to reach as many women in medically underserved communities as possible, including older women, women without health insurance, and women who are members of racial and ethnic minorities. Age and income requirements vary by state.

The program provides both screening and diagnostic services, including:

• clinical breast exams
• mammograms
• Pap tests
• diagnostic testing for women whose screening results are abnormal
• surgical consultations
• referrals to treatment

Though the program is administered within each state, tribe, or territory, the Centers for Disease Control and Prevention (CDC) provides matching funds and support to each program.

Since 1991 when the program began, it has provided more than 7.8 million screening exams to underserved women and diagnosed more than 35,000 breast cancers, more than 114,000 pre-cancerous cervical lesions, and more than 2,100 cervical cancers. Now that the program is firmly established, doctors are detecting new cancers at their earliest stages, leading to longer-term survival. These accomplishments demonstrate a truly nationwide effort. Unfortunately, however, due to limited resources, only about 1 in 5 eligible women aged 40 to 64 is served nationwide.

As noted above, all 50 states plus the District of Columbia have opted to provide Medicaid coverage for women diagnosed with breast cancer through the NBCCEDP, so that they may receive cancer treatment.

Each state's Department of Health will have information on how to contact the nearest CDC screening and early detection program in your area. For more information, please contact the CDC at 1-800-CDC-INFO ( 1-800-232-4636) or through their web site at www.cdc.gov/cancer.

Medicare

Since 1998, Medicare has covered mammograms once every 12 months for all women with Medicare aged 40 and over. (Women are eligible for Medicare if they are age 65 and older, are disabled, or have end-stage renal disease.) Medicare also pays for a clinical breast exam once every 24 months along with a pelvic exam. These benefits are not subject to the usual Medicare Part B deductible, but the standard 20% co-pay applies.

Medicare also covers an initial preventive physical exam for all new Medicare beneficiaries within 6 months of enrolling in Medicare. The "Welcome to Medicare" exam includes measurements of height, weight, and blood pressure, in addition to referrals for prevention and early detection services already covered under Medicare, such as mammograms.

Additional resources

More information from your American Cancer Society

The following information may also be helpful to you. These materials may be ordered from our toll-free number, 1-800-227-2345, or found on our Web site, www.cancer.org.

• Breast Cancer (also available in Spanish)

• Breast Cancer Dictionary (also available in Spanish)

• Breast Cancer in Men

• Is Having an Abortion Linked Breast Cancer?

• DES Exposure: Questions and Answers

• For Women Facing a Breast Biopsy

• Genetic Testing: What You Need to know

• Mammograms and Other Breast Imaging Procedures

• Medicines to Reduce Breast Cancer Risk

• Non-cancerous Breast Conditions (also available in Spanish)

National organizations and web sites*

In addition to the American Cancer Society, other sources of patient information and support include:

Centers for Disease Control and Prevention (CDC)
Cancer Prevention and Control Program
Toll-free number: 1-800-232-4636 (1-800-CDC-INFO)
Web site: www.cdc.gov/cancer
Information about the National Breast and Cervical Cancer Early Detection Program

National Cancer Institute (NCI)
Toll-free number: 1-800-4-CANCER (1-800-422-6237)
Web site: www.cancer.gov
General breast cancer information

*Inclusion on this list does not imply endorsement by the American Cancer Society.

No matter who you are, we can help. Contact us any time, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org.

References

American Cancer Society. Detailed Guide: Breast Cancer. 2009. Available at: www.cancer.org/docroot/CRI/CRI_2_3x.asp?dt=5. Accessed September 22, 2009.

Centers for Disease Control and Prevention. National Breast and Cervical Cancer Early Detection Program. Available at: www.cdc.gov/cancer/nbccedp/about.htm. Accessed September 22, 2009.

Pisano ED, Gatsonis C, Hendrick E, et al. Diagnostic performance of digital versus film mammography for breast-cancer screening. N Engl J Med. 2005;353:1773�1783.

Saslow D, Boetes C, Burke W, et al for the American Cancer Society Breast Cancer Advisory Group. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007;57:75�89.

Smith RA, Saslow D, Sawyer KA, et al. American Cancer Society guidelines for breast cancer screening: Update 2003. CA Cancer J Clin. 2003;53:141�169.