What is breast cancer?

Breast cancer is a type of uncontrolled growth of abnormal cells that can develop in one of several areas of the breast, including the ducts that carry milk to the nipple, the small sacs that produce milk (lobules) and the nonglandular tissue.

The main forms of invasive breast cancer are:

Invasive ductal carcinoma This type of breast cancer develops in the milk ducts and accounts for about 75% of cases. It can break through the duct wall and invade the fatty tissue of the breast, then spread (metastasize) to other parts of the body through the bloodstream or lymphatic system.
Invasive lobular carcinoma This type of breast cancer accounts for about 15% of cases. It originates in the breast's milk-producing lobules. It can spread to the breast's fatty tissue and other places in the body.
Medullary, mucinous and tubular carcinomas These slow-growing types of breast cancer represent about 8% of all breast cancers.
Paget's disease This type represents about 1% of breast cancers. It starts in the milk ducts of the nipple and can spread to the dark circle around the nipple (areola). Women who get Paget's disease usually have a history of nipple crusting, scaling, itching or inflammation.
Inflammatory carcinoma This type accounts for about 1% of all cases. Of all breast cancers, inflammatory carcinoma is the most aggressive and difficult to treat, because it spreads so quickly.

As more women have regular mammograms, doctors are detecting many more noninvasive or precancerous conditions before they become full-blown cancer. These conditions include:

Ductal carcinoma in situ (DCIS) This occurs when cancer cells fill the ducts but haven't spread through the walls into fatty tissue. Nearly all women diagnosed at this early stage can be cured. Without treatment, about 25% of DCIS cases will lead to invasive breast cancer within 10 years.
Lobular carcinoma in situ (LCIS) This is less of a threat than DCIS. It develops in the breast's milk-producing lobules. LCIS doesn't require treatment, but it does increase a woman's risk of developing cancer in other areas of both breasts.

Breast cancer is the second most common cancer (after skin cancer) in women in the United States, with approximately 181,000 cases expected in 2007. It causes the death of more than 40,000 women each year, and is the second leading cause of cancer death in women. A woman's risk of developing breast cancer increases with age; more than three out of four breast cancer cases occur in women over age 50. Other risk factors include:

A family history of breast cancer
A prior history of breast cancer or certain other abnormalities of the breast tissue
Increased exposure to the female hormone estrogen in any of three ways: having a first menstrual period before age 13, entering menopause after age 51 or using estrogen replacement therapy
Never having been pregnant, or having a first pregnancy after age 30
Being overweight, especially after menopause
Drinking alcohol (cancer risk doubles with three or more drinks per day)
Having a sedentary lifestyle with little regular exercise

Although breast cancer is much more common in women than in men, about 1,400 new cases of breast cancer are diagnosed each year in men in the United States, with 290 deaths.

Symptoms

Symptoms of breast cancer include:

A lump or thickening in the breast or under the arm
A clear or bloody discharge from the nipple
Crusting or scaling of the nipple
Nipples that don't stick out (inverted)
Redness or swelling of the breast
Dimpling on the breast skin resembling the texture of an orange
A change in the contours of the breast, such as one being higher than the other
A sore or ulcer on the skin of the breast that does not heal

Diagnosis

Your doctor will ask about factors that increase your risk of breast cancer, especially a family history of the illness. Your doctor will look for the symptoms described above, including a lump or thickening in the breast, nipple inversion or discharge, swelling or changes in breast contour, redness or dimpling of breast skin, and enlarged lymph nodes in the armpit.

If your doctor discovers a lump during a physical examination or your screening mammogram detects an area of abnormal breast tissue, your doctor will recommend an evaluation for breast cancer. In some cases, the next step is an ultrasound, which can confirm whether the lump is a solid tumor or a fluid-filled, noncancerous cyst. If the lump is solid, your doctor probably will recommend a breast biopsy, in which breast tissue is removed for laboratory testing. Sometimes, your doctor will recommend a biopsy without doing an ultrasound first. Several types of breast biopsy are currently available, including fine-needle biopsy, core biopsy, stereotactic needle biopsy and surgical biopsy, which involves the removal of all or part of the breast lump.

The biopsy will confirm if you have breast cancer. Depending on the specific type of biopsy, and whether neighboring lymph nodes were removed, the biopsy report may clarify the extent of the spread of the cancer, whether the tumor cells are estrogen-receptor positive or negative, and whether there are too many copies of the HER-2 gene in the cancer cells. This information will help determine the type of recommended treatment.

Expected Duration

Breast cancer will continue to grow and spread until it is treated.

Prevention

Although there are no guarantees, you can take some steps to help prevent breast cancer:

Don't smoke.
Maintain a healthy weight.
Exercise regularly.
Limit your use of alcohol. If you do drink, you may be able to decrease your risk of breast cancer by taking a folate supplement.
Follow a healthy diet low in fat and high in cruciferous vegetables (broccoli, Brussels sprouts and cauliflower).
Have your doctor examine your breasts every three years if you are under age 40 and every year if you are over 40.
Have regular mammograms. Mammograms can detect breast cancer two to five years before a tumor becomes large enough to be felt as a lump. Women who believe they may be at especially high risk of hereditary breast cancer should consult with a genetic counselor before testing.

Also, researchers have found mutations in two genes BRCA1 and BRCA2 that are associated with hereditary breast cancer. Although blood tests can identify women who have these genetic mutations, researchers have not yet determined who should be screened or what to recommend if the mutations are found.

Treatment

Treatment for breast cancer usually begins with a decision about the type of surgery. The two options are removing the entire breast (mastectomy) or removing only the cancerous lump and a small amount of healthy tissue around it (lumpectomy). After surgery, your doctor may recommend radiation therapy, chemotherapy, hormonal therapy or a combination of therapies. Additional therapies decrease the risk of cancer returning or spreading.

Radiation therapy usually is recommended after a lumpectomy to destroy any cancer cells left behind and to prevent the cancer from returning. Without radiation therapy, the odds of the cancer returning increase by about 25%.

The need for chemotherapy depends on how much the cancer has spread. In some cases, chemotherapy is recommended before surgery to shrink a large tumor so that it can be removed more easily. Chemotherapy is usually necessary if cancer returns. A form of chemotherapy called hormonal chemotherapy usually is recommended when the pathology report shows that the cancer is estrogen-receptor positive. In hormonal chemotherapy, the drug used most often is tamoxifen (Nolvadex). Tamoxifen locks estrogen out of breast cancer cells that are estrogen-receptor positive, which may reduce the cancer recurrence rate by up to 30%.

Medicines called aromatase inhibitors are another form of hormonal therapy. These drugs include anastrazole (Arimidex), exemestane (Aromasin) and letrozole (Femara). They decrease the amount of estrogen in the body by blocking estrogen production in all other tissues except the ovaries. These drugs are most useful in menopausal women, because the ovaries stop making estrogen after menopause.

Treatment for DCIS is a lumpectomy usually followed by radiation therapy or simple mastectomy with the removal of a limited number of lymph nodes. A mastectomy may be recommended if DCIS occurs in more than one location or if the tumor cells look especially worrisome on biopsy.

Though mastectomies are sometimes still used to treat DCIS, a lumpectomy with radiation is also commonly used. In some women, a lumpectomy without radiation may be effective.

LCIS doesn't lead to cancer so no treatment is required. However, women with this condition are more likely to develop cancer in other areas of their breasts, so they should have regular mammograms and breast exams by a doctor. To decrease breast cancer risk, some women use hormonal therapy, such as tamoxifen.

When To Call A Professional

Call your doctor immediately if you find a lump or abnormal thickening in your breast. Call your doctor if you notice a nipple is inverted, discharge from a nipple, a swelling in your breast or a change in breast contour, or redness or dimpling of breast skin.

Prognosis

Early diagnosis significantly improves the outlook for women with breast cancer. If the tumor is small and confined to the breast, more than 90% of women survive for at least 5 years after the diagnosis. However, if the disease spreads throughout the body before diagnosis, the 5-year survival rate drops to less than 20%.

Additional Info

National Cancer Institute (NCI)

U.S. National Institutes of Health
Public Inquiries Office
Building 31, Room 10A03
31 Center Drive, MSC 8322
Bethesda, MD 20892-2580
Phone: 301-435-3848
Toll-Free: 1-800-422-6237
TTY: 1-800-332-8615
Email: cancergovstaff@mail.nih.gov
http://www.nci.nih.gov/

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