Cancer begins in cells, the building blocks that make up all tissues and organs of the body, including the breast.
Normal cells in the breast and other parts of the body grow and divide to form new cells as they are needed. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body doesn’t need them, and old or damaged cells don’t die as they should. The buildup of extra cells often forms a mass of tissue called a lump, growth, or tumor.
Tumors in the breast can be benign (not cancer) or malignant (cancer):
- Are usually not harmful
- Rarely invade the tissues around them
- Don’t spread to other parts of the body
- Can be removed and usually don’t grow back
- May be a threat to life
- Can invade nearby organs and tissues (such as the chest wall)
- Can spread to other parts of the body
- Often can be removed but sometimes grow back
Breast cancer cells can spread by breaking away from a breast tumor. They can travel through blood vessels or lymph vessels to reach other parts of the body. After spreading, cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues.
For example, breast cancer cells may spread first to nearby lymph nodes. Groups of lymph nodes are near the breast under the arm (axilla), above the collarbone, and in the chest behind the breastbone.
When breast cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary (original) tumor. For example, if breast cancer spreads to a lung, the cancer cells in the lung are actually breast cancer cells. The disease is metastatic breast cancer, not lung cancer. For that reason, it’s treated as breast cancer, not lung cancer.
Type of Breast Cancer
Breast cancer is the most common type of cancer among women in the United States (other than skin cancer). In 2013, more than 232,000 American women will be diagnosed with breast cancer.
The most common type of breast cancer is ductal carcinoma. This cancer begins in cells that line a breast duct. About 7 of every 10 women with breast cancer have ductal carcinoma.
The second most common type of breast cancer is lobular carcinoma. This cancer begins in a lobule of the breast. About 1 of every 10 women with breast cancer has lobular carcinoma.
Other women have a mixture of ductal and lobular type or they have a less common type of breast cancer.
The stage of breast cancer depends on the size of the breast tumor and whether it has spread to lymph nodes or other parts of the body.
Doctors describe the stages of breast cancer using the Roman numerals 0, I, II, III, and IV and the letters A, B, and C.
A cancer that is Stage I is early-stage breast cancer, and a cancer that is Stage IV is advanced cancer that has spread to other parts of the body, such as the liver.
The stage often is not known until after surgery to remove the tumor in the breast and one or more underarm lymph nodes.
Stage 0 is carcinoma in situ. In ductal carcinoma in situ (DCIS), abnormal cells are in the lining of a breast duct, but the abnormal cells have not invaded nearby breast tissue or spread outside the duct.
The breast tumor is no more than 2 centimeters (no more than 3/4 of an inch) across. Cancer has not spread to the lymph nodes.
The tumor is no more than 2 centimeters across. Cancer cells are found in lymph nodes.
The tumor is no more than 2 centimeters across, and the cancer has spread to underarm lymph nodes.
Or, the tumor is between 2 and 5 centimeters (between 3/4 of an inch and 2 inches) across, but the cancer hasn’t spread to underarm lymph nodes.
The tumor is between 2 and 5 centimeters across, and the cancer has spread to underarm lymph nodes.
Or, the tumor is larger than 5 centimeters across, but the cancer hasn’t spread to underarm lymph nodes.
The breast tumor is no more than 5 centimeters across, and the cancer has spread to underarm lymph nodes that are attached to each other or nearby tissue. Or, the cancer may have spread to lymph nodes behind the breastbone.
Or, the tumor is more than 5 centimeters across. The cancer has spread to underarm lymph nodes that may be attached to each other or nearby tissue. Or, the cancer may have spread to lymph nodes behind the breastbone but not spread to underarm lymph nodes.
The breast tumor can be any size, and it has grown into the chest wall or the skin of the breast. The breast may be swollen or the breast skin may have lumps.
The cancer may have spread to underarm lymph nodes, and these lymph nodes may be attached to each other or nearby tissue. Or, the cancer may have spread to lymph nodes behind the breastbone.
The breast cancer can be any size, and it has spread to lymph nodes behind the breastbone and under the arm. Or, the cancer has spread to lymph nodes above or below the collarbone.
The tumor can be any size, and cancer cells have spread to other parts of the body, such as the lungs, liver, bones, or brain.
Women with breast cancer have many treatment options. Treatment options include:
- Radiation therapy
- Hormone therapy
- Targeted therapy
You may receive more than one type of treatment.
The treatment that’s best for one woman may not be best for another. The treatment that’s right for you depends mainly on:
- The stage of breast cancer
- Whether the tumor has hormone receptors
- Whether the tumor has too much HER2
- Your general health
In addition, your treatment plan depends on:
- The size of the tumor in relation to the size of your breast
- Whether you have gone through menopause
At any stage of disease, care is available to control pain and other symptoms, to relieve the side effects of treatment, and to ease emotional concerns. You can get information about coping on NCI’s website at http://www.cancer.gov/cancertopics/coping.
Also, you can get information about coping from NCI’s Cancer Information Service at 1-800-4-CANCER (1-800-422-6237). Or, chat using NCI’s instant messaging service, LiveHelp.
Doctors Who Treat Breast Cancer
Your health care team will include specialists, and may include the following specialists:
- Surgeon: This type of doctor can perform surgery. You may want to find a breast cancer surgeon.
- Medical oncologist: A medical oncologist is a doctor who specializes in treating cancer with drugs, such as chemotherapy, hormone therapy, and targeted therapy.
- Radiation oncologist: A radiation oncologist is a doctor who specializes in treating cancer with radiation therapy.
Your health care team may also include a plastic surgeon or reconstructive surgeon, an oncology nurse, a physical therapist, a social worker, and a registered dietitian.
Your health care team can describe your treatment choices, the expected results of each treatment, and the possible side effects. Because cancer treatments often damage healthy cells and tissues, side effects are common. These side effects depend on many factors, including the type of treatment. Side effects may not be the same for each woman, and they may even change from one
treatment session to the next.
Before treatment starts, ask your health care team about possible side effects and how treatment may change your normal activities.
You and your health care team can work together to develop a treatment plan that meets your medical and personal needs.
You may want to talk with your health care team about taking part in a research study (clinical trial) of new treatment methods. Research studies are an important option for women at any stage of breast cancer.
Questions you may want to ask your doctor about treatment choices:
- What are my treatment choices? Which do you recommend for me? Why?
- What are the expected benefits of each kind of treatment?
- What are the risks and possible side effects of each treatment?
- How can the side effects be managed?
- What can I do to prepare for treatment?
- Will I need to stay in the hospital? If so, for how long?
- What is the treatment likely to cost? Will my insurance cover it?
- How will treatment affect my normal activities?
- Would a research study (clinical trial) be right for me?
Before starting treatment, you might want a second opinion about your treatment plan. Some women worry that the doctor will be offended if they ask for a second opinion. Usually the opposite is true. Most doctors welcome a second opinion. And many health insurance companies will pay for a second opinion if you or your doctor requests it. Some companies actually require a second opinion.
If you get a second opinion, the second doctor may agree with your first doctor’s treatment plan. Or, the second doctor may suggest another approach. Either way, you have more information and perhaps a greater sense of control. You can feel more confident about the decisions you make, knowing that you’ve looked at all of your options.
It may take some time and effort to gather your medical records and see another doctor. In most cases, it’s not a problem to take several weeks to get a second opinion. The delay in starting treatment usually will not make treatment less effective. To make sure, you should discuss this delay with your doctor.
Surgery is the most common treatment for breast cancer. There are several kinds of surgery. Your surgeon can describe each kind of surgery, compare the benefits and risks, and help youdecide which kind might be best for you:
Removing part of the breast
Breast-sparing surgery is an operation to remove the cancer and a small amount of the normal tissue that surrounds it. This is also called breast-conserving surgery. It can be a lumpectomy or a segmental mastectomy (also called a partial mastectomy).A woman usually has radiation therapy after breast-sparing surgery to kill cancer cells that may remain in the breast area.
Some women will have more tissue removed but not the whole breast. For these women, the surgeon will remove lymph nodes under the arm and some of the lining over the chest muscles below the tumor.
Removing the whole breast
Surgery to remove the whole breast (or as much of the breast tissue as possible) is a mastectomy. In some cases, a skin-sparing mastectomy may be an option. For this approach, the surgeon removes as little skin as possible.
- In total (simple) mastectomy, the surgeon removes the whole breast but not the underarm lymph nodes.
- 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 may also be taken out to make it easier to remove the lymph nodes.
The choice between breast-sparing surgery and mastectomy depends on many factors:
- The size, location, and stage of the tumor
- The size of your breast
- Certain features of the cancer
- How you feel about how surgery will change your breast
- How you feel about radiation therapy
- Your ability to travel to a radiation treatment center for daily treatment sessions
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 the Tests section.)
After mastectomy, you may choose to have breast reconstruction. This is plastic surgery to rebuild the shape of the breast. If you’re considering breast reconstruction, talk with a plastic surgeon before having cancer surgery.
It’s common to feel tired or weak for a while after surgery for breast cancer. The time it takes to heal is different for each woman.
Surgery causes pain and tenderness, and the skin where your breast was removed may feel tight. Your arm and shoulder muscles may feel stiff and weak, and your neck and back may hurt. Medicine can help control your pain. Before surgery, discuss the plan for pain relief with your health care team. After surgery, they can adjust the plan if you need more pain control.
Any kind of surgery carries a risk of infection, bleeding, or other problems. Tell your health care team right away if you develop any problems.
Removing the underarm lymph nodes 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.
Always protect the arm and hand on the treated side of your body from cuts, burns, or other injuries. Remind nurses not to measure your blood pressure or give you injections on the treated side of your body. Information about preventing and treating lymphedema is available on NCI’s website at http://www.cancer.gov/cancertopics/coping and from NCI’s Cancer Information Service at 1-800-4-CANCER (1-800-422-6237) or LiveHelp.
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, or upper arm. These feelings may go away within a few weeks or months.
You can find pictures and more information about breast cancer surgery on NCI’s website at http://www.cancer.gov/cancertopics/types/breast.
Questions you may want to ask your doctor about surgery:
- What kinds of surgery can I consider? Is breast-sparing surgery an option for me? Is a skin-sparing mastectomy an option Which operation do you recommend for me? Why?
- Will any lymph nodes be removed? How many? Why?
- How will I feel after the operation? Will I have to stay in the hospital? What are the risks of surgery?
- How many surgeries for breast cancer have you done?
- Will I need to learn how to take care of myself or my incision when I get home?
- Where will the scars be? What will they look like?
- If I decide to have plastic surgery to rebuild my breast, how and when can that be done? Can
you suggest a plastic surgeon for me to contact?
- Will I have to do special exercises to help regain motion and strength in my arm and shoulder? Will a physical therapist or nurse show me how to do the exercises?
Radiation therapy 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 chest area. Women usually have radiation therapy after breast-sparing surgery, but it’s sometimes used after mastectomy too.
You can get radiation therapy to treat breast cancer in two ways:
- Machine outside the body (external radiation therapy): The radiation comes from a large machine outside the body. You’ll go to a hospital or clinic for treatment. Usually, women get treatment once a day, 5 days a week for 3 to 6 weeks. Each treatment session lasts only a few minutes. External radiation is the most common type used for breast cancer.
- Material inside the body (brachytherapy): The doctor will place 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. This method of radiation therapy may be repeated every day for a week.
Side effects depend mainly on the type of radiation and how much is given. Ask your health care team to describe what you can expect.
It’s common for the skin in the treated area to become red, dry, tender, and itchy. Check with your doctor before using lotion, cream, or deodorant on the treated area. After treatment is over, the skin will slowly heal. However, there may be a lasting change in the color of your skin.
With either type of radiation therapy, 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.
You’re likely to become tired during radiation therapy, especially in the later weeks of treatment. Although getting enough rest is important, most people say they feel better when they exercise every day. Try to go for a short walk, do gentle stretches, or do yoga.
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.
The NCI booklet Radiation Therapy and You has helpful ideas for coping with side effects.
Questions you may want to ask your doctor about radiation therapy
- Which type of radiation therapy can I consider? Are both types an option for me?
- When will treatment start? When will it end? How often will I have treatment?
- How will I feel during treatment? Will I need to stay in the hospital? Will I be able to drive myself to and from treatment?
- What can I do to take care of myself before, during, and after treatment?
- How will we know the treatment is working?
- Will radiation therapy harm my skin?
- How will my chest look afterward?
- Are there any lasting effects?
- What is the chance that the cancer will come back in my breast?
Hormone therapy can also be called anti-hormone treatment. If lab tests show that your breast cancer cells have hormone receptors, then hormone therapy may be an option. (See the part about Lab Tests with Breast Tissue.) Hormone therapy keeps the cancer cells from getting or using the natural hormones (estrogen and progesterone) they need to grow.
If you have not gone through menopause, the options for hormone therapy include…
- A drug that blocks estrogen’s activity in the body (tamoxifen)
- Surgery to remove your ovaries (which make estrogen)
- A drug that reduces the amount of estrogen made by the ovaries (LH-RH agonist)
If you have gone through menopause, the options include…
- A drug that prevents the body from making estrogen (aromatase inhibitor)
The side effects of hormone therapy depend on the type used. The most common side effects are hot flashes, vaginal discharge, and nausea.
The NCI fact sheet Hormone Therapy for Breast Cancer has information about the use and side effects of hormone therapy.
Chemotherapy uses drugs to kill cancer cells. It may be given to women with Stage I, II, III, or IV breast cancer. Chemotherapy may be given before or after surgery.
The drugs for breast cancer are usually given directly into a vein (intravenously) through a thin needle or as a pill. You may receive a combination of drugs.
You may receive chemotherapy in a clinic, at the doctor’s office, or at home. It’s unusual for a woman to 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.
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).
If you have not yet gone through menopause, some anticancer drugs may damage the ovaries and cause hot flashes, vaginal dryness, and other menopause symptoms. Your menstrual periods may no longer be regular or may stop, and you may lose the ability to become pregnant. The older you are, the more likely that this damage to the ovaries will be permanent. Women who may want to get pregnant later on should ask their health care team about ways to preserve their eggs before treatment starts.
On the other hand, other anticancer drugs don’t damage the ovaries and you may remain able to become pregnant during chemotherapy. Before treatment begins, talk with your doctor about birth control because many anticancer drugs given during the first trimester are known to cause birth defects.
The NCI booklet Chemotherapy and You has ideas for coping with side effects.
Women whose lab tests show that their breast cancer cells have too much HER2 protein may receive targeted therapy. The targeted therapies used to treat breast cancer block cancer cell growth by blocking the action of the extra HER2 protein.
These drugs may be given intravenously or as a pill. The side effects depend mainly on which drug is given. Possible side effects include nausea, vomiting, and diarrhea. The drugs may also cause heart damage, heart failure, and serious breathing problems. During treatment, your doctor will watch for signs of heart and lung problems.
You may want to read the NCI fact sheet Targeted Cancer Therapies.
Questions you may want to ask your doctor about hormone therapy, chemotherapy, or targeted therapy
- What drugs will I be taking? What will they do?
- When will treatment start? When will it end? How often will I have treatments?
- Where will I have treatment?
- What can I do to take care of myself during treatment?
- How will we know the treatment is working?
- Which side effects should I tell you about?
- Will there be long-term side effects?
A woman who plans to have a mastectomy has a choice about whether or not to have surgery to rebuild the shape of the breast (breast reconstruction). Instead of breast reconstruction, a woman could choose to wear a breast form (a device that replaces the breast), wear padding inside her bra, or do nothing. All of these options have pros and cons. What is right for one woman may not be right for another.
Breast reconstruction may be done at the same time as the mastectomy, or it may be done later on. If radiation therapy is part of the treatment plan, some doctors suggest waiting until after radiation therapy is complete.
If you’re thinking about breast reconstruction, talk to a plastic surgeon before the mastectomy, even if you plan to have your reconstruction later on.
A surgeon can reconstruct the breast in many ways. Some women choose to have breast implants, which are filled with saline or silicone gel. You can read about breast implants on the Food and Drug Administration’s website at http://www.fda.gov.
Another method of breast reconstruction is to create a breast shape using tissue taken from another part of your body. The plastic surgeon can take skin, muscle, and fat from your lower abdomen, back, or buttocks.
The type of reconstruction that is best for you depends on your age, body type, and the type of cancer surgery that you had. A plastic surgeon can help you decide.
Questions you may want to ask your doctor about breast reconstruction
- Which type of surgery would give me the best results? How will I look afterward?
- When can my reconstruction begin?
- How many surgeries will I need?
- What are the risks at the time of surgery? Later?
- Will I have scars? Where? What will they look like?
- If tissue from another part of my body is used, will there be any permanent changes where the tissue was removed?
- What activities should I avoid after surgery? When can I return to my normal activities?
- Will I need follow-up care?
- How much will reconstruction cost? Will my health insurance pay for it?
Eating well is important before, during, and after cancer treatment. You need the right amount of calories to maintain a good weight. You also need enough protein to keep up your strength. Eating well may help you feel better and have more energy.
Sometimes, especially during or soon after treatment, you may not feel like eating. You may be uncomfortable or tired. You may find that foods don’t taste as good as they used to. In addition, poor appetite, nausea, vomiting, mouth blisters, and other side effects of treatment can make it hard for you to eat. On the other hand, some women treated for breast cancer may have a problem with weight gain.
Your doctor, a registered dietitian, or another health care provider can suggest ways to help you meet your nutrition needs. Also, the NCI booklet Eating Hints has many useful recipes and lists of foods that can help with side effects.
You’ll need regular checkups (such as every 3 to 6 months) after treatment for breast cancer. Checkups help ensure that any changes in your health are noted and treated if needed. If you have any health problems between checkups, contact your doctor.
Checkups help detect:
- Breast cancer that comes back after treatment: Breast cancer may return in the breast or chest wall. Or, it may return in any other part of the body, such as the bones, liver, lungs, or brain.
- Health problems that can result from cancer treatment
- A new breast cancer
Checkups usually include an exam of the neck, underarm, chest, and breast areas. Since a new breast cancer may develop, you should have regular mammograms. You probably won’t need a mammogram of a reconstructed breast or if you had a mastectomy without reconstruction. Your doctor may order other imaging procedures or lab tests.