Breast Cancer

Breast cancer is a potentially dangerous tumor that develops in the cells of the breast. Cancer cells sometimes spread from the breast to other parts of the body.


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In the United States, breast cancer is a very common cancer among women, second only to skin cancer. Breast cancer also occurs in men, but much more rarely. Deaths from breast cancer have been reduced in recent years because more effective treatments are now available, and because these cancers are found earlier when they are easier to treat.

How Does Breast Cancer Start?

Humans are mammals, and all mammals have breasts, which are the organs that make milk to feed babies. In the breast are lobules (LOB-yools) that look like bunches of grapes. Channels, or ducts, from the lobules enable milk to flow to the nipple. The lobules and ducts are surrounded by fatty tissue and ligaments called stroma (STRO-ma).

Cancer in situ

Breast cancer begins when a single cell in a duct or lobule undergoes changes (mutations) that cause it to start growing out of control. At first, even though the cells are growing very rapidly, they stay within the duct or lobule. At this stage the cancer is called cancer in situ. Later, the cells may break out of the duct or lobule into the fat and surrounding tissue, where they continue to divide and multiply. Since a tumor needs nourishment to grow, it sends out signals in the form of proteins that cause new blood vessels to form and support it. Without a blood supply, a tumor will die.


Cancer cells may enter the bloodstream, where they may be killed by the immune system (the body's defense against disease). If they are not killed by the immune system, the cancer cells may travel to distant organs of the body, settle there, grow, and divide. This process of spread is called metastasis (me-TAS-ta-sis).

Breast cancer cells are most likely to find their way to the lungs, liver, and bones. Cancer is named for the place where it starts. So even when breast cancer travels to the lungs or the bones, it is still called breast cancer.

Who Gets Breast Cancer?

No one knows yet exactly what causes breast cancer to start. It is impossible to catch it from another person.

Can teenagers get breast cancer?

Breast cancer in teenagers is very rare. A girl whose breasts are developing may feel some discomfort from time to time. And once her periods start, she may retain water during the last part of her cycle, which can cause her breasts to ache. But these pains are a normal part of the body's functioning. They are not a sign of cancer.

Anatomy of the breast. Ducts carry milk from the lobules to the nipple. The lobules and ducts are surrounded by fatty tissue and ligaments called stroma.
Anatomy of the breast. Ducts carry milk from the lobules to the nipple. The lobules and ducts are surrounded by fatty tissue and ligaments called stroma.

BRCA1, BRCA2, and estrogen

Women who inherit some mutated genes from their parents are at higher risk of getting breast cancer. These genes, called BRCA1 and BRCA2, are involved in only a small fraction of breast cancer cases. Researchers suspect that natural substances called hormones, especially the female hormone estrogen, play a role in promoting some types of breast cancer.

Family history

A woman whose mother, sister, or daughter has had breast cancer has twice the risk of getting it as a woman with no family history of breast cancer. However, most women diagnosed with breast cancer do not (to their knowledge) have a family history of breast cancer. A woman who has already had breast cancer in one breast is at higher risk of getting it in the other breast.


Age is also a risk factor. Older women have a higher risk of developing breast cancer. Another risk factor is early age for first menstrual period as well as late age for menopause. Women who have their first child after the age of 30, or who do not have any children, also have a higher risk.

Diet and life style

Rates of breast cancer vary around the world, and it appears these differences are related to diet or life style. For example, women in Asia have only one fifth to one tenth the risk of getting breast cancer as women in North America or Western Europe. But when Asian women move to Western countries, their risk increases to the same level as the local population. The reasons why are not clear.

Women, Breast Cancer,
and Mammograms

  • All women are at risk for breast cancer. Over 60 percent of U.S. women diagnosed with breast cancer do not have a family history of the disease.
  • Currently, breast cancer occurs in one out of every eight U.S. women.
  • The early detection of breast cancer by mammograms increases the chance of successful treatment.
  • Some doctors believe that every woman should have her first mammogram by age 35. This first mammogram should be saved as a baseline for comparison with future mammograms.
  • Women between the ages of 40 and 50 should have a mammogram every one to two years.
  • Women over the age of 50 should have a mammogram every year.

What Happens When Women Have Breast Cancer?

Signs and symptoms

Usually, a woman will notice a painless lump in her breast. Or her doctor may feel the lump during a routine examination. The shape, color, or texture of the breast or nipple may change or the nipple may be tender or have a discharge. Sometimes cancers are found before symptoms occur. In these cases, routine or "screening" mammography (mam-MOG-ra-fee) (x-ray examination of the breasts) shows changes that indicate a possibility of cancer, which must be checked.


If screening tests or a woman's symptoms suggest cancer, the doctor may request a biopsy (BY-op-see). In this procedure, a small amount of tissue is removed from the abnormal area of the breast and examined under a microscope. Most biopsies show that the woman does not have cancer. If the tissue is benign (be-NINE) (not cancer), no further treatment may be needed. But if the diagnosis is cancer, then the woman will want to learn about the disease and discuss her options for treatment with health professionals, her friends, and family.


For tumors that do not appear to have spread, it may be possible to remove only the tumor and leave most of the breast. This is called a lumpectomy (lump-EK-to-mee). Sometimes, however, it may be necessary to perform a mastectomy (mas-TEK-to-mee), an operation that removes the breast. Whether mastectomy or lumpectomy is the best choice depends on the size and sometimes the kind of tumor.

Men and Breast Cancer

  • About 1 percent of all cases of breast cancer occur in men.
  • A family history of breast cancer is a risk factor for men as well as for women.
  • Breast cancer in men is often not detected until the cancer is advanced and more difficult to treat.
  • Breast cancer in men usually shows up as a lump beneath the breast area, fixation of skin to the lump, and discharge from the nipple.
  • Treatment usually involves surgical removal of the lump, followed by chemotherapy or radiation therapy.
  • Treatment and cure rates for men are similar to those for women.

3,000 Years of Breast Cancer
Research and Treatment

A description of "bulging tumors" being burned or cut out of the breast can be found in the Edwin Smith papyrus from Thebes, dated 1600 B.C.E.

Ancient Greek women sought help from Aesculapius (es-ku-LA-pe-us), their mythical god of healing. Aesculapian temples were filled with offerings, including carvings of excised tumorous breasts. The women hoped their gifts would prompt an explanation of their disease or convey thanks to the god for his healing power.

The Greek physician Hippocrates (c. 460—c. 375 B.C.E.) emphasized the importance of diet and the environment for the management of breast cancer. During the second century, the Roman physician Galen (130-200 A.D.) focused his research on a theory that excess black bile caused cancer, and that treatment required that the bile be removed by means of bloodletting.

The bloodletting technique prevailed until the 1500s, when medieval doctors began returning to surgical treatment of breast cancer.

Follow-up treatment may include radiation therapy and anti-cancer medication, called chemotherapy (kee-mo-THER-a-pee), to kill any remaining cancer cells and to prevent them from growing back. The choice of follow-up treatment depends on the kind of tumor and whether it appears to have spread to the lymph nodes * or other parts of the body.

Can Breast Cancer Be Prevented?

There is no sure way to prevent breast cancer. It may be possible for women to reduce their risk of breast cancer by not drinking too much alcohol, by eating a healthy diet, and by getting regular exercise. Because detecting cancer early improves the chance of treating it with a better outcome, or even curing it, women 40 and older should have a screening mammogram and a physical exam to check their breasts every year. Women aged 20 to 39 should have a breast exam every three years. And all women aged 20 and older should learn how to examine their own breasts and check them once a month.

Will There Ever Be a Way of Preventing Breast Cancer?

Because chemotherapy kills healthy cells as well as cancer cells, research efforts in the area of drug treatment are concentrating on drugs that do less damage to healthy cells than current treatments. Researchers also are studying how best to use the information from genetic tests for breast cancer genes to help a woman lower her risk of getting breast cancer.

* lymph nodes are bean-sized round or oval masses of immune system tissue that filter bodily fluids before they enter the bloodstream, helping to keep out bacteria and other undesirable substances.

Support groups

For women with breast cancer, talking to other women who are living with the disease can be a very comforting experience. For women whose breast cancer has come back or spread, it may even do more than that. One study showed that women with metastatic breast cancer who participated in support groups lived an average of almost two years longer than women who did not.

Women who have just been diagnosed with breast cancer also may find it helpful to meet and to talk to women who had breast cancer 10 or 15 years earlier and who are now living happy, healthy lives.

The American Cancer Society and the National Alliance of Breast Cancer Organizations provide information about finding support groups.

Imaging the Body:
wilhelm Konrad RÖntgen

In 1895, the German physics professor Wilhelm Konrad Röntgen (1845-1923) discovered a new kind of ray that he found mysterious enough to call "X." Röntgen's "x-rays" (later called "roentgen rays") were an alternative to light that made it possible to see structures within the body. Among the first photographs Röontgen took were of the bones in his wife's hand.

Today, Röntgen's invention is used to take pictures of many parts of the body, including the breast, making early detection of breast cancer possible and saving or extending the lives of millions of women around the world. Röntgen was awarded the Nobel Prize in physics in 1901.

X-ray mammograms are far from perfect. They miss some cancers, and they return uncertain results in some healthy women, causing them to undergo the anxiety and discomfort of biopsies to rule out cancer. Scientists are continuing research efforts to improve breast imaging.

Tamoxifen research

An effective treatment for many women with breast cancer is a drug called tamoxifen. This drug works against the hormones that stimulate the cells in the breast to grow and are believed to be a factor in many breast cancers. Tamoxifen is so effective that it was approved in the late 1990s for use by women who do not have breast cancer but who are at a high risk of getting it. Researchers are investigating similar drugs that do not have the side effects of tamoxifen and might be safe enough for healthy women at lower risk to use as a way of preventing breast cancer.

Screening (routine) mammograms contribute to earlier detection of cancer and improved treatment outcomes. © 1991 David Weinstein and Associates/Custom Medical Stock Photo.
Screening (routine) mammograms contribute to earlier detection of cancer and improved treatment outcomes.
© 1991 David Weinstein and Associates/Custom Medical Stock Photo.

What Is It Like to Live with Breast

Treatment for breast cancer can be very unpleasant. Mastectomy is emotionally difficult, and some women, about 1 in 10, may get serious swelling in their arms as a result of the surgery. As with almost any kind of cancer, a person must learn to live with the fear that the cancer might return. Side effects of chemotherapy may make it impossible for a young woman with breast cancer to have children. Many women lose their hair temporarily. If the cancer has spread, it becomes important to recognize, plan for, and cope with the prospect of dying. And because breasts are a part of the body that we consider very personal and that a woman associates with many things she cherishes, including love and children, she may worry that the people closest to her see her differently. Many women who have had mastectomies are able to have breast reconstructive surgery, which can restore a more normal appearance following breast removal. Many women with breast cancer find support groups very helpful in dealing with the stresses of the illness. It is important for patients, friends, and family to remember that people are much more than the sum of their body parts. No one is to blame for cancer. Love and understanding may help to make even the most difficult situation bearable.



Love, Susan M. Dr. Susan Love's Breast Book, second edition. Reading, Massachusetts: Addison-Wesley, 1995.

Tomlinson, Theresa. Dancing through the Shadows. London: Dorling-Kindersly, 1997.


U.S. National Cancer Institute, Bethesda, MD 20892. The NCI coordinates the government's cancer research program, and provides information about cancer to patients, their families, and the public. Its fact sheet What You Need to Know About Breast Cancer is posted at its website.
Telephone 800-4-CANCER

American Cancer Society (ACS), 1599 Clifton Road NE, Atlanta, GA 30329-4251. ACS is a national, not-for-profit society whose purpose is to provide unbiased, accurate, up-to-date health information about cancer.
Telephone 800-ACS-2345

National Alliance of Breast Cancer Organizations (NABCO). NABCO's newsletter NABCO News publishes information about breast cancer research, and its website helps people find local support groups.
Telephone 888-806-2226

Y-Me National Breast Cancer Hotline, 212 West Van Buren, Chicago, IL 60607. A national organization that offers information and support to anyone who has been touched by breast cancer.
Telephone 800-221-2141

University of Pennsylvania Cancer Center. The OncoLink website at the University of Pennsylvania posts information about all aspects of cancer.

See also
Fibrocystic Breast Disease

Also read article about Breast Cancer from Wikipedia

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