Cancer Information

What You Should Know About...BREAST CANCER

Breast Biology

The breasts sit on the chest muscles that cover the ribs. Each breast is made of 15 to 20 lobes. Lobes contain many smaller lobules. Lobules contain groups of tiny glands that can produce milk. Milk flows from the lobules through thin tubes called ducts to the nipple. The nipple is in the center of a dark area of skin called the areola. Fat fills the spaces between the lobules and ducts.

The breasts also contain lymph vessels. These vessels lead to small, round organs called lymph nodes. Groups of lymph nodes are near the breast in the axilla (underarm), above the collarbone, in the chest behind the breastbone, and in many other parts of the body. The lymph nodes trap bacteria, cancer cells, or other harmful substances.

Breast Cancer Basics

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.

When breast cancer cells spread, the cancer cells are often found in lymph nodes near the breast. Also, breast cancer can spread to almost any other part of the body. The most common are the bones, liver, lungs, and brain. The new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer. For that reason, it is treated as breast cancer, not bone cancer. Doctors call the new tumor "distant" or metastatic disease.

Risk Factors for Breast Cancer

No one knows the exact causes of breast cancer. Doctors often cannot explain why one woman develops breast cancer and another does not. They do know that bumping, bruising, or touching the breast does not cause cancer. And breast cancer is not contagious. You cannot "catch" it from another person. Research has shown that women with certain risk factors are more likely than others to develop breast cancer. A risk factor is something that may increase the chance of developing a disease. Studies have found the following risk factors for breast cancer:

• Age: The chance of getting breast cancer goes up as a woman gets older. Most cases of breast cancer occur in women over 60. This disease is not common before menopause.
• Personal history of breast cancer: A woman who had breast cancer in one breast has an increased risk of getting cancer in her other breast.
• Family history: A woman's risk of breast cancer is higher if her mother, sister, or daughter had breast cancer. The risk is higher if her family member got breast cancer before age 40. Having other relatives with breast cancer (in either her mother's or father's family) may also increase a woman's risk.
• Certain breast changes: Some women have cells in the breast that look abnormal under a microscope.
• Gene changes: Changes in certain genes increase the risk of breast cancer. These genes include BRCA1, BRCA2, and others. Tests can sometimes show the presence of specific gene changes in families with many women who have had breast cancer. Health care providers may suggest ways to try to reduce the risk of breast cancer, or to improve the detection of this disease in women who have these changes in their genes.
• Reproductive and menstrual history:
  
  • The older a woman is when she has her first child, the greater her chance of breast cancer. o Women who had their first menstrual period before age 12 are at an increased risk of breast cancer.
  • Women who went through menopause after age 55 are at an increased risk of breast cancer.
  • Women who never had children are at an increased risk of breast cancer.
  • Women who take menopausal hormone therapy with estrogen plus progestin after menopause also appear to have an increased risk of breast cancer.
• Race: Breast cancer is diagnosed more often in white women than Latina, Asian, or African American women.
• Radiation therapy to the chest: Women who had radiation therapy to the chest (including breasts) before age 30 are at an increased risk of breast cancer.
• Breast density: Breast tissue may be dense or fatty. Older women whose mammograms show more dense tissue are at increased risk of breast cancer.
• Taking DES (diethylstilbestrol): DES was given to some pregnant women in the United States between about 1940 and 1971. (It is no longer given to pregnant women.) Women who took DES during pregnancy may have a slightly increased risk of breast cancer. The possible effects on their daughters are under study.
• Being overweight or obese after menopause: The chance of getting breast cancer after menopause is higher in women who are overweight or obese.
• Lack of physical activity: Women who are physically inactive throughout life may have an increased risk of breast cancer. Being active may help reduce risk by preventing weight gain and obesity.
• Drinking alcohol: Studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.

Other possible risk factors are under study. Researchers are studying the effect of diet, physical activity, and genetics on breast cancer risk. They are also studying whether certain substances in the environment can increase the risk of breast cancer.

Common symptoms of breast cancer include:

• A change in how the breast or nipple feels
  • A lump or thickening in or near the breast or in the underarm area
  • Nipple tenderness
• A change in how the breast or nipple looks
  • A change in the size or shape of the breast
  • A nipple turned inward into the breast
  • The skin of the breast, areola, or nipple may be scaly, red, or swollen. It may have ridges or pitting so that it looks like the skin of an orange. 
• Nipple discharge (fluid)

Early breast cancer usually does not cause pain. Still, a woman should see her health care provider about breast pain or any other symptom that does not go away. Most often, these symptoms are not due to cancer. Other health problems may also cause them. Any woman with these symptoms should tell her doctor so that problems can be diagnosed and treated as early as possible.

Screening and Early Diagnosis:

Screening for breast cancer before there are symptoms can be important. Screening can help doctors find and treat cancer early. Treatment is more likely to work well when cancer is found early. Your doctor may suggest the following screening tests for breast cancer:

• Screening mammogram
• Clinical breast exam
• Breast self-exam

Incidence and Mortality Rate Trends

In the United States, breast cancer is the most common non-skin cancer and the second leading cause of cancer-related death in women. Each year, a small number of men are also diagnosed with or die from breast cancer. Although the breast cancer diagnosis rate has increased, the overall breast cancer death rate has dropped steadily since the early 1990s.

Although the incidence of breast cancer is highest in Whites, African Americans have higher mortality rates than any other racial or ethnic group in the United States. The gap in mortality between African Americans and Whites has widened in recent years. It is estimated that approximately $8.1 billion is spent in the United States each year on treatment of breast cancer.

 

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