Breast Cancer


What Is It?

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

The main forms of breast cancer are:

  • Invasive ductal carcinoma — This type of breast cancer develops in the milk ducts and accounts for about 79 percent of cases. It can break through the duct wall and invade the breast’s fatty tissue, then metastasize (spread) to other parts of the body through the bloodstream or lymphatic system.

  • Invasive lobular carcinoma — This type of breast cancer accounts for about 10 percent of cases and originates in the breast’s milk-producing lobules. It also can spread to the breast’s fatty tissue and other places in the body.

  • Medullary, mucinous and tubular carcinomas — These are three slow-growing types of breast cancer. Together they represent about 10 percent of all breast cancers.

  • Paget’s disease — This type represents about 1 percent of breast cancers. It starts in the milk ducts of the nipple and can spread to the areola (dark circle around the nipple). 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 percent 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 also detecting many more noninvasive or precancerous conditions before they become full-blown cancer. These conditions include:

  • Ductal carcinoma in situ (DCIS) — DCIS occurs when cancer cells fill the ducts but haven’t yet spread through the walls into fatty tissue. Nearly all women diagnosed at this early stage can be cured. Without treatment, about 25 percent of DCIS cases will lead to invasive breast cancer within 10 years.

  • Lobular carcinoma in situ (LCIS) — LCIS is less common and 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 breast cancer.

Breast cancer is the second most common cancer (after skin cancer) in U.S. women, with approximately 212,600 cases diagnosed in 2003. It causes the death of more than 40,000 women each year, and remains the leading cause of death in women between the ages of 40 and 55. 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 of breast cancer include:

  • A lump or thickening in the breast or under the arm
  • A clear or bloody discharge from the nipple
  • Persistent crusting or scaling of the nipple
  • Inverted nipples
  • 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


Your doctor will ask about factors that increase your risk of breast cancer, especially a family history of the illness. He or she also 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 in your breast 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 examination to 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 — removal of breast tissue 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 whether or not you have breast cancer. Depending on the specific type of biopsy, and whether neighboring lymph nodes were also removed and examined, the biopsy report also may clarify the extent of cancer spread, 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. These factors will help determine the type of recommended treatment .

Expected Duration

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


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).
  • Examine your own breasts every month.
  • Have a clinical breast examination in your doctor’s office 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. Although the specific frequency of mammograms is controversial, many experts still recommend annual mammograms for women older than 40.

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 for breast cancer almost always begins with a decision about the type of surgery. The two surgical options are removing the entire affected breast (mastectomy) or removing only the malignant lump and a margin of healthy tissue around it (lumpectomy). Surgery may be followed by radiation therapy, and sometimes chemotherapy, to destroy any remaining cancer cells.

Radiation therapy, sometimes called radiotherapy, almost always is recommended after 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 percent.

The need for chemotherapy depends on how much the cancer has spread. In some cases, chemotherapy will be recommended before surgery to shrink a large tumor so that it can be removed more easily. Chemotherapy is almost always necessary if cancer recurs. 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 tamoxifen (Nolvadex) is taken daily, by mouth, for two to five years. Tamoxifen locks estrogen out of breast cancer cells that are estrogen-receptor positive, which may reduce the cancer recurrence rate by up to 30 percent.

In the past, precancerous DCIS was treated as if it were breast cancer, but now it appears that less aggressive treatments may be equally effective. Though mastectomy sometimes still is done for DCIS, lumpectomy with radiation also is commonly done. In some women, lumpectomy without radiation also may be effective. Because LCIS itself doesn’t lead to cancer, no treatment is required, but women with this condition should have regular mammograms and breast exams by a physician.

When To Call A Professional

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


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

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.