Cancer Guide

What is Breast Cancer?

Our Radiation Oncologists have extensive experience in treating breast cancer. They work seamlessly with breast cancer specialists, including surgeons and medical oncologists to ensure that patients receive the best comprehensive care possible. In fact, our special breast radiation therapy program that combines medical expertise, sophisticated technology, and compassion helps distinguish us as a premier radiation oncology practice for treating breast cancer patients.

Definition

Breast cancer is one of the most common cancers in the United States. Radiation therapy is an integral part of the cancer care for many breast cancer patients. Radiation treatments are often part of an overall cancer care regimen that may include surgery, chemotherapy, and/or hormonal therapy.

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Causes

When you're told that you have breast cancer, it's natural to wonder what may have caused the disease. However, no one knows the exact causes of breast cancer. Doctors seldom know why one woman develops breast cancer and another doesn't.

Doctors do know that bumping, bruising, or touching the breast does not cause cancer. And breast cancer is not contagious. You can't catch it from another person.

Doctors also know that women with certain risk factors are more likely than others to develop breast cancer. A risk factor is something that may increase the chance of getting a disease.

Some risk factors (such as drinking alcohol) can be avoided. But most risk factors (such as having a family history of breast cancer) can't be avoided.

Studies have found the following risk factors for breast cancer:

  • Age: The chance of getting breast cancer increases as you get older. Most women are over 60 years old when they are diagnosed.
  • Personal health history: Having breast cancer in one breast increases your risk of getting cancer in your other breast. Also, having certain types of abnormal breast cells (atypical hyperplasia, lobular carcinoma in situ [LCIS], or ductal carcinoma in situ [DCIS]) increases the risk of invasive breast cancer. These conditions are found with a breast biopsy.
  • Family health history: Your risk of breast cancer is higher if your mother, father, sister, or daughter had breast cancer. The risk is even higher if your family member had breast cancer before age 50. Having other relatives (in either your mother's or father's family) with breast cancer or ovarian cancer may also increase your risk.
  • Certain genome changes: Changes in certain genes, such as BRCA1 or BRCA2, substantially increase the risk of breast cancer. Tests can sometimes show the presence of these rare, specific gene changes in families with many women who have had breast cancer, and health care providers may suggest ways to try to reduce the risk of breast cancer or to improve the detection of this disease in women who have these genetic changes.

Also, researchers have found specific regions on certain chromosomes that are linked to the risk of breast cancer. If a woman has a genetic change in one or more of these regions, the risk of breast cancer may be slightly increased. The risk increases with the number of genetic changes that are found. Although these genetic changes are more common among women than BRCA1 or BRCA2, the risk of breast cancer is far lower.

  • Radiation therapy to the chest: Women who had radiation therapy to the chest (including the breasts) before age 30 are at an increased risk of breast cancer. This includes women treated with radiation for Hodgkin lymphoma. Studies show that the younger a woman was when she received radiation treatment, the higher her risk of breast cancer later in life.
  • Reproductive and menstrual history:
    • The older a woman is when she has her first child, the greater her chance of breast cancer.
    • Women who never had children are at an increased risk of breast cancer.
    • Women who had their first menstrual period before age 12 are at an increased risk of breast cancer.
    • Women who went through menopause after age 55 are at an increased risk of breast cancer.
    • Women who take menopausal hormone therapy for many years have an increased risk of breast cancer.
  • Race: In the United States, breast cancer is diagnosed more often in white women than in African American/black, Hispanic/Latina, Asian/Pacific Islander, or American Indian/Alaska Native women.
  • Breast density: Breasts appear on a mammogram (breast X-ray) as having areas of dense and fatty (not dense) tissue. Women whose mammograms show a larger area of dense tissue than the mammograms of women of the same age are at increased risk of breast cancer.
  • History of taking DES: DES was given to some pregnant women in the United States between about 1940 and 1971. (It is no longer given to pregnant women.) Women who took DES during pregnancy may have a slightly increased risk of breast cancer. The possible effects on their daughters are under study.
  • Being overweight or obese after menopause: The chance of getting breast cancer after menopause is higher in women who are overweight or obese.
  • Lack of physical activity: Women who are physically inactive throughout life may have an increased risk of breast cancer.
  • Drinking alcohol: Studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.

Having a risk factor does not mean that a woman will get breast cancer. Most women who have risk factors never develop breast cancer.

Many other possible risk factors have been studied. For example, researchers are studying whether women who have a diet high in fat or who are exposed to certain substances in the environment have an increased risk of breast cancer. Researchers continue to study these and other possible risk factors.

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Symptoms

Early breast cancer usually doesn't cause symptoms, but as the tumor grows, it can change how the breast looks or feels. The common changes include:

  • A lump or thickening in or near the breast or in the underarm area
  • A change in the size or shape of the breast
  • Dimpling or puckering in the skin of the breast
  • A nipple turned inward into the breast
  • Discharge (fluid) from the nipple, especially if it's bloody
  • Scaly, red, or swollen skin on the breast, nipple, or areola (the dark area of skin at the center of the breast). The skin may have ridges or pitting so that it looks like the skin of an orange.

You should see your health care provider about any symptom that does not go away. Most often, these symptoms are not due to cancer. Another health problem could cause them. If you have any of these symptoms, you should tell your health care provider so that the problems can be diagnosed and treated.

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Diagnosis

Your doctor can check for breast cancer before you have any symptoms. During an office visit, your doctor will ask about your personal and family medical history. You'll have a physical exam. Your doctor may order one or more imaging tests, such as a mammogram.

Doctors recommend that women have regular clinical breast exams and mammograms to find breast cancer early. Treatment is more likely to work well when breast cancer is detected early.

You may want to read the NCI booklet Understanding Breast Changes. It describes types of breast changes and tests used to find changes.

Clinical Breast Exam

During a clinical breast exam, your health care provider checks your breasts. You may be asked to raise your arms over your head, let them hang by your sides, or press your hands against your hips.

Your health care provider looks for differences in size or shape between your breasts. The skin of your breasts is checked for a rash, dimpling, or other abnormal signs. Your nipples may be squeezed to check for fluid.

Using the pads of the fingers to feel for lumps, your health care provider checks your entire breast, underarm, and collarbone area. A lump is generally the size of a pea before anyone can feel it. The exam is done on one side and then the other. Your health care provider checks the lymph nodes near the breast to see if they are enlarged.

If you have a lump, your health care provider will feel its size, shape, and texture. Your health care provider will also check to see if the lump moves easily. Benign lumps often feel different from cancerous ones. Lumps that are soft, smooth, round, and movable are likely to be benign. A hard, oddly shaped lump that feels firmly attached within the breast is more likely to be cancer, but further tests are needed for diagnosis.

Mammogram

A mammogram is an X-ray picture of tissues inside the breast. Mammograms can often show a breast lump before it can be felt. They also can show a cluster of tiny specks of calcium. These specks are called microcalcifications. Lumps or specks can be from cancer, precancerous cells, or other conditions. Further tests are needed to find out if abnormal cells are present.

Before they have symptoms, women should get regular screening mammograms to detect breast cancer early:

  • Women in their 40s and older should have mammograms every 1 or 2 years.
  • Women who are younger than 40 and have risk factors for breast cancer should ask their health care provider whether to have mammograms and how often to have them.

If the mammogram shows an abnormal area of the breast, your doctor may order clearer, more detailed images of that area. Doctors use diagnostic mammograms to learn more about unusual breast changes, such as a lump, pain, thickening, nipple discharge, or change in breast size or shape. Diagnostic mammograms may focus on a specific area of the breast. They may involve special techniques and more views than screening mammograms.

To learn more about mammograms, you may want to read the NCI fact sheet Mammograms.

Other Imaging Tests

If an abnormal area is found during a clinical breast exam or with a mammogram, the doctor may order other imaging tests:

  • Ultrasound: A woman with a lump or other breast change may have an ultrasound test. An ultrasound device sends out sound waves that people can't hear. The sound waves bounce off breast tissues. A computer uses the echoes to create a picture. The picture may show whether a lump is solid, filled with fluid (a cyst), or a mixture of both. Cysts usually are not cancer, but a solid lump may be cancer.
  • MRI: MRI uses a powerful magnet linked to a computer. It makes detailed pictures of breast tissue. These pictures can show the difference between normal and diseased tissue.

Biopsy

A biopsy is the removal of tissue to look for cancer cells. A biopsy is the only way to tell for sure if cancer is present.

You may need to have a biopsy if an abnormal area is found. An abnormal area may be felt during a clinical breast exam but not seen on a mammogram. Or an abnormal area could be seen on a mammogram but not be felt during a clinical breast exam. In this case, doctors can use imaging procedures (such as a mammogram, an ultrasound, or MRI) to help see the area and remove tissue.

Your doctor may refer you to a surgeon or breast disease specialist for a biopsy. The surgeon or doctor will remove fluid or tissue from your breast in one of several ways:

  • Fine-needle aspiration biopsy: Your doctor uses a thin needle to remove cells or fluid from a breast lump.
  • Core biopsy: Your doctor uses a wide needle to remove a sample of breast tissue.
  • Skin biopsy: If there are skin changes on your breast, your doctor may take a small sample of skin.
  • Surgical biopsy: Your surgeon removes a sample of tissue.

A pathologist will check the tissue or fluid removed from your breast for cancer cells. If cancer cells are found, the pathologist can tell what kind of cancer it is. The most common type of breast cancer is ductal carcinoma. It begins in the cells that line the breast ducts. Lobular carcinoma is another type. It begins in the lobules of the breast.

Lab Tests with Breast Tissue

If you are diagnosed with breast cancer, your doctor may order special lab tests on the breast tissue that was removed:

  • Hormone receptor tests: Some breast tumors need hormones to grow. These tumors have receptors for the hormones estrogen, progesterone, or both. If the hormone receptor tests show that the breast tumor has these receptors, then hormone therapy is most often recommended as a treatment option. See the Hormone Therapy section.
  • HER2/neu test: HER2/neu protein is found on some types of cancer cells. This test shows whether the tissue either has too much HER2/neu protein or too many copies of its gene. If the breast tumor has too much HER2/neu, then targeted therapy may be a treatment option. See the Targeted Therapy section.

It may take several weeks to get the results of these tests. The test results help your doctor decide which cancer treatments may be options for you.

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Treatment

Women with breast cancer have many treatment options. The treatment that's best for one woman may not be best for another.

The options are surgery, radiation therapy, hormone therapy, chemotherapy, and targeted therapy. You may receive more than one type of treatment. The treatment options are described below.

Surgery and radiation therapy are types of local therapy. They remove or destroy cancer in the breast.

Hormone therapy, chemotherapy, and targeted therapy are types of systemic therapy. The drug enters the bloodstream and destroys or controls cancer throughout the body.

The treatment that's right for you depends mainly on the stage of the cancer, the results of the hormone receptor tests, the result of the HER2/neu test, and your general health. See Treatment choices by stage.

You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods. Clinical trials are an important option for women at any stage of breast cancer. See Taking Part in Cancer Research.

Your doctor can describe your treatment choices, the expected results, and the possible side effects. Because cancer therapy often damages healthy cells and tissues, side effects are common. Before treatment starts, ask your health care team about possible side effects, how to prevent or reduce these effects, and how treatment may change your normal activities.

You may want to know how you will look during and after treatment. You and your health care team can work together to develop a treatment plan that meets your medical and personal needs.

Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat breast cancer include surgeons, medical oncologists, and radiation oncologists. You also may be referred to a plastic surgeon or reconstructive surgeon. Your health care team may also include an oncology nurse and a registered dietitian.

At any stage of disease, supportive care is available to control pain and other symptoms, to relieve the side effects of treatment, and to ease emotional concerns. Information about such care is available on the NCI Web site at http://www.cancer.gov/cancertopics/coping and from the NCI Cancer Information Service at 1-800-4-CANCER (1-800-422-6237) or at LiveHelp (http://www.cancer.gov/help).

Surgery

Surgery is the most common treatment for breast cancer. (See below for pictures of the types of surgery.) Your doctor can explain each type, discuss and compare the benefits and risks, and describe how each will change the way you look:

  • Breast-sparing surgery: This is an operation to remove the cancer but not the breast. It's also called breast-conserving surgery. It can be a lumpectomy or a segmental mastectomy (also called a partial mastectomy). Sometimes an excisional biopsy is the only surgery a woman needs because the surgeon removes the whole lump.
  • Mastectomy: This is an operation to remove the entire breast (or as much of the breast tissue as possible). In some cases, a skin-sparing mastectomy may be an option. For this approach, the surgeon removes as little skin as possible.

The surgeon usually removes one or more lymph nodes from under the arm to check for cancer cells. If cancer cells are found in the lymph nodes, other cancer treatments will be needed. (For more about information about lymph node biopsy, see Staging.)

You may choose to have breast reconstruction. This is plastic surgery to rebuild the shape of the breast. It may be done at the same time as the cancer surgery or later. If you're considering breast reconstruction, you may wish to talk with a plastic surgeon before having cancer surgery. See Breast Reconstruction.

In modified radical mastectomy, the surgeon removes the whole breast and most or all of the lymph nodes under the arm. Often, the lining over the chest muscles is removed. A small chest muscle also may be taken out to make it easier to remove the lymph nodes.

The time it takes to heal after surgery is different for each woman. Surgery causes pain and tenderness. Medicine can help control the pain. Before surgery, you should discuss the plan for pain relief with your doctor or nurse. After surgery, your doctor can adjust the plan if you need more relief.

Any kind of surgery also carries a risk of infection, bleeding, or other problems. You should tell your health care team right away if you develop any problems.

You may feel off balance if you've had one or both breasts removed. You may feel more off balance if you have large breasts. This imbalance can cause discomfort in your neck and back.

Also, the skin where your breast was removed may feel tight. Your arm and shoulder muscles may feel stiff and weak. These problems usually go away. The doctor, nurse, or physical therapist can suggest exercises to help you regain movement and strength in your arm and shoulder. Exercise can also reduce stiffness and pain. You may be able to begin gentle exercise within days of surgery.

Because nerves may be injured or cut during surgery, you may have numbness and tingling in your chest, underarm, shoulder, and upper arm. These feelings usually go away within a few weeks or months, but for some women, numbness does not go away.

Removing the lymph nodes under the arm slows the flow of lymph fluid. The fluid may build up in your arm and hand and cause swelling. This swelling is called lymphedema. It can develop soon after surgery or months or even years later. You'll always need to protect the arm and hand on the treated side of your body from cuts, burns, or other injuries. Information about preventing and treating lymphedema is available on the NCI Web site at http://www.cancer.gov/cancertopics/coping and from Information Specialists at 1-800-4-CANCER (1-800-422-6237) or LiveHelp (http://www.cancer.gov/help).

Radiation Therapy

Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cells only in the part of the body that is treated. Radiation therapy may be used after surgery to destroy breast cancer cells that remain in the area.

Doctors use two types of radiation therapy to treat breast cancer. Some women receive both types:

  • External radiation therapy: The radiation comes from a large machine outside the body. You will go to a hospital or clinic for treatment. Treatments are usually 5 days a week for 4 to 6 weeks. External radiation is the most common type used for breast cancer.
  • Internal radiation therapy (implant radiation therapy or brachytherapy): The doctor places one or more thin tubes inside the breast through a tiny incision. A radioactive substance is loaded into the tube. The treatment session may last for a few minutes, and the substance is removed. When it's removed, no radioactivity remains in your body. Internal radiation therapy may be repeated every day for a week.

Side effects depend mainly on the dose and type of radiation. It's common for the skin in the treated area to become red, dry, tender, and itchy. Your breast may feel heavy and tight. Internal radiation therapy may make your breast look red or bruised. These problems usually go away over time.

Bras and tight clothes may rub your skin and cause soreness. You may want to wear loose-fitting cotton clothes during this time.

Gentle skin care also is important. You should check with your doctor before using any deodorants, lotions, or creams on the treated area. Toward the end of treatment, your skin may become moist and "weepy." Exposing this area to air as much as possible can help the skin heal. After treatment is over, the skin will slowly heal. However, there may be a lasting change in the color of your skin.

You're likely to become very tired during radiation therapy, especially in the later weeks of treatment. Resting is important, but doctors usually advise patients to try to stay active, unless it leads to pain or other problems.

You may wish to discuss with your doctor the possible long-term effects of radiation therapy. For example, radiation therapy to the chest may harm the lung or heart. Also, it can change the size of your breast and the way it looks. If any of these problems occur, your health care team can tell you how to manage them.

Hormone Therapy

Hormone therapy may also be called anti-hormone treatment. If lab tests show that the tumor in your breast has hormone receptors, then hormone therapy may be an option. (See Lab Tests with Breast Tissue.) Hormone therapy keeps cancer cells from getting or using the natural hormones (estrogen and progesterone) they need to grow.

Options before menopause

If you have not gone through menopause, the options include:

  • Tamoxifen: This drug can prevent the original breast cancer from returning and also helps prevent the development of new cancers in the other breast. As treatment for metastatic breast cancer, tamoxifen slows or stops the growth of cancer cells that are in the body. It's a pill that you take every day for 5 years.

    In general, the side effects of tamoxifen are similar to some of the symptoms of menopause. The most common are hot flashes and vaginal discharge. Others are irregular menstrual periods, thinning bones, headaches, fatigue, nausea, vomiting, vaginal dryness or itching, irritation of the skin around the vagina, and skin rash. Serious side effects are rare, but they include blood clots, strokes, uterine cancer, and cataracts. You may want to read the NCI fact sheet Tamoxifen.
  • LH-RH agonist: This type of drug can prevent the ovaries from making estrogen. The estrogen level falls slowly. Examples are leuprolide and goserelin. This type of drug may be given by injection under the skin in the stomach area. Side effects include hot flashes, headaches, weight gain, thinning bones, and bone pain.
  • Surgery to remove your ovaries: Until you go through menopause, your ovaries are your body's main source of estrogen. When the surgeon removes your ovaries, this source of estrogen is also removed. (A woman who has gone through menopause wouldn't benefit from this kind of surgery because her ovaries produce much less estrogen.) When the ovaries are removed, menopause occurs right away. The side effects are often more severe than those caused by natural menopause. Your health care team can suggest ways to cope with these side effects.

Options after menopause

If you have gone through menopause, the options include:

  • Aromatase inhibitor: This type of drug prevents the body from making a form of estrogen (estradiol). Examples are anastrazole, exemestane, and letrozole. Common side effects include hot flashes, nausea, vomiting, and painful bones or joints. Serious side effects include thinning bones and an increase in cholesterol.
  • Tamoxifen: Hormone therapy is given for at least 5 years. Women who have gone through menopause receive tamoxifen for 2 to 5 years. If tamoxifen is given for less than 5 years, then an aromatase inhibitor often is given to complete the 5 years. Some women have hormone therapy for more than 5 years. See above for more information about tamoxifen and its possible side effects.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. The drugs that treat breast cancer are usually given through a vein (intravenous) or as a pill. You'll probably receive a combination of drugs.

You may receive chemotherapy in an outpatient part of the hospital, at the doctor's office, or at home. Some women need to stay in the hospital during treatment.

The side effects depend mainly on which drugs are given and how much. Chemotherapy kills fast-growing cancer cells, but the drugs can also harm normal cells that divide rapidly:

  • Blood cells: When drugs lower the levels of healthy blood cells, you're more likely to get infections, bruise or bleed easily, and feel very weak and tired. Your health care team will check for low levels of blood cells. If your levels are low, your health care team may stop the chemotherapy for a while or reduce the dose of the drug. There are also medicines that can help your body make new blood cells.
  • Cells in hair roots: Chemotherapy may cause hair loss. If you lose your hair, it will grow back after treatment, but the color and texture may be changed.
  • Cells that line the digestive tract: Chemotherapy can cause a poor appetite, nausea and vomiting, diarrhea, or mouth and lip sores. Your health care team can give you medicines and suggest other ways to help with these problems.

Some drugs used for breast cancer can cause tingling or numbness in the hands or feet. This problem often goes away after treatment is over.

Other problems may not go away. For example, some of the drugs used for breast cancer may weaken the heart. Your doctor may check your heart before, during, and after treatment. A rare side effect of chemotherapy is that years after treatment, a few women have developed leukemia (cancer of the blood cells).

Some anticancer drugs can damage the ovaries. If you have not gone through menopause yet, you may have hot flashes and vaginal dryness. Your menstrual periods may no longer be regular or may stop. You may become infertile (unable to become pregnant). For women over the age of 35, this damage to the ovaries is likely to be permanent.

On the other hand, you may remain able to become pregnant during chemotherapy. Before treatment begins, you should talk with your doctor about birth control because many drugs given during the first trimester are known to cause birth defects.

You may want to read the NCI booklet Chemotherapy and You.

Targeted Therapy

Some women with breast cancer may receive drugs called targeted therapy. Targeted therapy uses drugs that block the growth of breast cancer cells. For example, targeted therapy may block the action of an abnormal protein (such as HER2) that stimulates the growth of breast cancer cells. (For information about HER2, see Lab Tests with Breast Tissue.)

Trastuzumab (Herceptin®) or lapatinib (TYKERB®) may be given to a woman whose lab tests show that her breast tumor has too much HER2:

  • Trastuzumab: This drug is given through a vein. It may be given alone or with chemotherapy. Side effects that most commonly occur during the first treatment include fever and chills. Other possible side effects include weakness, nausea, vomiting, diarrhea, headaches, difficulty breathing, and rashes. These side effects generally become less severe after the first treatment. Trastuzumab also may cause heart damage, heart failure, and serious breathing problems. Before and during treatment, your doctor will check your heart and lungs. The NCI fact sheet Herceptin® (Trastuzumab) has more information.
  • Lapatinib: The tablet is taken by mouth. Lapatinib is given with chemotherapy. Side effects include nausea, vomiting, diarrhea, tiredness, mouth sores, and rashes. It can also cause red, painful hands and feet. Before treatment, your doctor will check your heart and liver. During treatment, your doctor will watch for signs of heart, lung, or liver problems.

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Cancer reference provided by the web site of the National Cancer Institute (www.cancer.gov). The NCI Web site is periodically revised, and content may be deleted or moved. We try to ensure that existing links will redirect to the new page(s).

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