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Alternative Names Return to topCancer - breast; Carcinoma - ductal; Carcinoma - lobular
Definition Return to top
Breast cancer is a cancer that starts in the tissues of the breast.
There are two main types of breast cancer:
In rare cases, breast cancer can start in other areas of the breast.
Many breast cancers are sensitive to the hormone estrogen. This means that estrogen causes the breast cancer tumor to grow. Such cancer is called estrogen receptor positive cancer or ER positive cancer.
Some women have what's called HER2-positive breast cancer. HER2 refers to a gene that helps cells grow, divide, and repair themselves. When cells have too many copies of this gene, cells -- including cancer cells -- grow faster. Experts think that women with HER2-positive breast cancer have a more aggressive disease and a higher risk of recurrence than those who do not have this type.
Causes Return to top
Over the course of a lifetime, 1 in 8 women will be diagnosed with breast cancer.
Risk factors you cannot change include:
Other risk factors include:
Breast implants, using antiperspirants, and wearing underwire bras do not raise your risk for breast cancer. There is no evidence of a direct link between breast cancer and pesticides.
The National Cancer Institute provides an online tool to help you figure out your risk of breast cancer. See: www.cancer.gov/bcrisktool
Symptoms Return to top
Early breast cancer usually does not cause symptoms. This is why regular breast exams are important. As the cancer grows, symptoms may include:
Men get breast cancer, too. Symptoms include breast lump and breast pain and tenderness.
Symptoms of advanced breast cancer may include:
Exams and Tests Return to top
The doctor will ask you about your symptoms and risk factors, and then perform a physical exam, which includes both breasts, armpits, and the neck and chest area. Additional tests may include:
If your doctor learns that you do have breast cancer, additional tests will be done to see if the cancer has spread. This is called staging. Staging helps guide future treatment and follow-up and gives you some idea of what to expect in the future.
Breast cancer stages range from 0 to IV. Breast cancer that has not spread is called ductal carcinoma in situ (DCIS), or noninvasive breast cancer. If it spreads, the cancer is called invasive breast cancer. The higher the number, the more advanced the cancer.
Treatment Return to top
Treatment is based on many factors, including type and stage of the cancer, whether the cancer is sensitive to certain hormones, and whether or not the cancer overproduces (overexpresses) a gene called HER2/neu.
In general, cancer treatments may include:
An example of hormonal therapy is the drug tamoxifen. This drug blocks the effects of estrogen, which can help breast cancer cells survive and grow. Most women with estrogen sensitive breast cancer benefit from this drug. A newer class of medicines called aromatase inhibitors, such as exemestane (Aromasin), have been shown to work just as well or even better than tamoxifen in post-menopausal women with breast cancer.
Targeted therapy, also called biologic therapy, is a newer type of cancer treatment. This therapy uses special anti-cancer drugs that identify certain changes in a cell that can lead to cancer. One such drug is trastuzumab (Herceptin). For women with stage IV HER2-positive breast cancer, Herceptin plus chemotherapy has been shown to be work better than chemotherapy alone. Studies have also shown that in women with early stage HER2-positive breast cancer, this medicine plus chemotherapy cuts the risk of the cancer coming back by 50%.
Cancer treatment may be local or systemic.
Most women receive a combination of treatments. For women with stage I, II, or III breast cancer, the main goal is to treat the cancer and prevent it from returning. For women with stage IV cancer, the goal is to improve symptoms and help them live longer. In most cases, stage IV breast cancer cannot be cured.
After treatment, some women will continue to medicaiotns such as tamoxifen for a period of time. All women will continue to have blood tests, mammograms, and other tests following treatment.
Support Groups Return to top
Talking about your disease and treatment with others who share common experiences and problems can be helpful. See: Cancer support group
Outlook (Prognosis) Return to top
How well you do after being treated for breast cancer depends on many things. The more advanced your cancer, the poorer the outcome.
The 5-year survival rate refers to the number of patients who live at least 5 years after their cancer is found. According to the American Cancer Society (ACS), the 5-year survival rates for persons with breast cancer that is appropriately treated are as follows:
Possible Complications Return to top
New, improved treatments are helping persons with breast cancer live longer than ever before. However, even with treatment, breast cancer can spread to other parts of the body. Sometimes, cancer returns even after the entire tumor is removed and nearby lymph nodes are found to be cancer-free.
You may experience side effects or complications from cancer treatment. For example, radiation therapy may cause temporary swelling of the breast, and aches and pains around the area. Ask your doctor about the side effects you may have during treatment.
When to Contact a Medical Professional Return to top
Contact your health care provider for an appointment if:
Prevention Return to top
Many risk factors -- such as your genes and family history -- cannot be controlled. However, a healthy diet and a few lifestyle changes may reduce your overall chance of cancer in general.
Breast cancer is more easily treated and often curable if it is found early.
Early detection involves:
Most experts recommend that women age 20 and older examine their breasts once a month during the week following the menstrual period.
Women between the ages 20 and 39 should have a doctor examine their breasts at least once every 3 years.
After age 40:
Mammography is the most effective way of detecting breast cancer early.
Certain women at high risk for breast cancer may have a breast MRI along with their yearly mammogram. Ask your doctor if your need an MRI.
Screening for breast cancer is a topic filled with controversy. A woman needs to have an informed and balanced discussion with her doctor, along with doing additional reading and researching on her own, to determine if mammography is right for her.
Tamoxifen is approved for breast cancer prevention in women aged 35 and older who are at high risk.
Women at very high risk for breast cancer may consider preventive (prophylactic) mastectomy, which is the surgical removal of the breasts. Possible candidates for this procedure may include those who have already had one breast removed due to cancer, women with a strong family history of breast cancer, and persons with genes or genetic mutations that raise their risk of breast cancer.
References Return to top
Lehman CD, Gatsonis C, Kuhl CK, et al. MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. N Engl J Med. 2007 Mar 29;356(13):1295-303. Epub 2007 Mar 28.
NCCN Clincal Practice Guidelines in Oncology: Breast cancer. 2nd ed. 2008. Accessed June 10, 2008.
Saslow D, Boetes C, Burke W, et al. American cancer society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007 Mar-Apr;57(2):75-89.Update Date: 12/1/2008 Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California.