Breast Cancer

Excluding cancers of the skin, breast cancer is the most common type of cancer among women in the United States, accounting for nearly one in three cancers diagnosed in U.S. women, according to the American Cancer Society (ACS). The ACS estimates 212,920 women were diagnosed with invasive breast cancer in 2006 while one in eight women will develop this type of cancer during her life. Men also can get breast cancer, although they make up less than one percent of all cases of breast cancer, according to the National Cancer Institute (NCI).

Death rates from breast cancer continue to fall despite a gradual, long-term increase in the rate of new diagnoses, states the NCI. Declining breast cancer death rates and rising breast cancer incidence rates during the 1990s have been attributed, in part, to increased use of mammography screening. The higher rates of late-stage disease in some population groups and geographic areas may reflect delayed access to care, often among women who lack health insurance and among recent immigrants.

Breast cancer begins with a growth or tumor. A tumor occurs when abnormal cells divide uncontrollably and form a mass. The tumor can be malignant (cancerous) or benign (noncancerous). In breast cancer, a mass of malignant tissue forms in the breast. The cells in this tumor divide without control or order, and they can invade and damage nearby tissues and organs. These abnormal cells can also break away from the tumor and enter the bloodstream or lymphatic system. That is how cancer spreads from the original (primary) site to other parts of the body (secondary sites). The process is called metastasis.

When breast cancer spreads, or metastasizes, cancer cells are found in the lymph nodes under the arm. If the cancer reaches these nodes, it means that cancer cells may have spread to other parts of the body through the bloodstream or lymphatic system. When this occurs, the disease is called metastatic breast cancer.

Risk Factors

Though physicians cannot always explain why one person gets cancer and another does not, some general patterns have emerged that suggest certain factors may increase a person’s chance of developing cancer. Anything that may increase a person’s chance of developing a disease is called a risk factor.

Some risk factors, like smoking, can be avoided. Others, like inherited genes, cannot. It is important to know, however, that avoiding risk factors does not guarantee a person will not get cancer.

Simply being a woman and getting older puts a person at risk for breast cancer. One or more of the following conditions places a woman at higher than average risk for the disease:

• Age 50 or over
• A personal or family history of breast cancer
• Exposure of the breast or chest to radiation
• Changes in certain genes, especially the BRCA1 and BRCA2 genes
• Benign breast disease or cystic breasts
• Menstrual periods that began early in life (before age 12) or menopause that began later in life (after age 55)
• Alcohol use (2 to 5 drinks daily)
• Not having children or having a first child after age 30
• Obesity
• Physical inactivity
• Long-term use (four years or more) of hormone replacement therapy (HRT) after menopause
• Weight gain and obesity after menopause

The American Cancer Society recommends women with no symptoms of breast cancer, who are 40 years of age or older, have a yearly mammogram and a clinical breast exam. Check with your physician if you find any change in your breast(s).

Source: American Cancer Society

Stages of Female Breast Cancer

• not found in the breast but is in one to three axillary lymph nodes (the lymph nodes under the arm)
• 2 centimeters or smaller and is found in the axillary lymph nodes; or
• larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes; or
• detected by sentinel node biopsy as microscopic disease in internal mammary nodes but not yet on imaging studies or by clinical exam; or
• larger than 2 cm and less than 5 cm but has not spread to axillary nodes.

Stage IIB: Cancer has not spread to distant sites, but is:

• larger than 2 centimeters but not larger than 5 centimeters and has spread to the axillary lymph nodes; or
• larger than 5 centimeters but has not spread to the axillary lymph nodes.

Stage IIIA: Cancer has not spread to distant sites, but is:

• not found in the breast, but in axillary lymph nodes that are attached to each other or to other structures; or
• 5 centimeters or smaller and has spread to axillary lymph nodes that are attached to each other or to other structures; or
• larger than 5 centimeters and has spread to axillary lymph nodes that may be attached to each other or to other structures.

Stage IIIB: Cancer has not spread to distant sites, but may be any size and:

• has spread to tissues near the breast (the skin or chest wall, including the ribs and muscles in the chest); and
• may have spread to lymph nodes within the breast or under the arm.

Stage IIIC: Cancer has not spread to distant sites, but:

• has spread to lymph nodes beneath the collarbone and near the neck; and
• may have spread to lymph nodes within the breast or under the arm and to tissues near the breast.

Stage IV: The cancer has spread to other organs of the body, most often the bones, lungs, liver, or brain.

Hereditary Breast Cancer

In recent years, several gene mutations have been found to be associated with an inherited increased risk for breast cancer. All of these genes normally work to help the body prevent cancer, particularly in the breasts. If a person is born with a mutation in only one copy of one of these genes, he/she is more likely to develop breast cancer.

Of the women in the U.S. who develop breast cancer each year, about 5 to 10 percent have a hereditary form of the disease. Inherited alterations in the BRCA1 and BRCA2 are involved in many cases of hereditary breast and ovarian cancers, according to the National Cancer Institute (NCI).

While the lifetime risk of developing breast cancer for a woman in the general population is approximately 13.2 percent, the risk increases from 36 to 85 percent for a woman with an altered BRCA1 or BRCA2 gene, according to the NCI. Women with these altered genes are also more likely to develop breast cancer at a younger age and are at higher risk of recurrence if they have had breast cancer. They are also more likely to have multiple close family members with the disease. Men with altered BRCA1 or BRCA2 gene have an increased risk for developing breast cancer, and possibly, prostate cancer compared to men without the altered genes.

These gene alterations are more common in certain populations of people, including those with:

• Ashkenazi Jewish ancestry
• Norwegian, Dutch or Icelandic ancestry
• Extensive family histories of breast and ovarian cancer
• Breast cancer diagnosed before the age of 50
• Bilateral breast cancer
• Breast and ovarian cancer diagnosed in the same person
• Male breast cancer

Testing for gene mutations related to breast cancer is now available, making it possible to identify families who have an inherited increased risk of breast and ovarian cancer. Treatment options for people with inherited increased risk include screening and preventive strategies.

Cancer Recurrence

Breast cancer can come back locally (in the breast or near the surgery scar) or in a distant area. Treatment of women whose breast cancer has recurred locally depends on their initial treatment. If the woman had breast conservation therapy, local recurrence in the breast is usually treated with mastectomy. If the initial treatment was mastectomy, recurrence near the mastectomy site is treated by removing the tumor whenever possible, occasionally followed by radiation therapy. In either case, hormone therapy and/or chemotherapy may be used after surgery and/or radiation therapy.

Women who have a distant recurrence involving organs such as the bones, lungs, or brain are treated similarly as those found to have stage IV breast cancer involving these organs at the time of initial diagnosis.

Breast Cancer in Men

Breast cancer is about 100 times more common among women, but occasionally occurs in men. Breast cancer accounts for about 0.22 percent (two tenths of a percent) of cancer deaths among men. The American Cancer Society estimates that in 2006, approximately 1,720 new cases of invasive breast cancer were diagnosed among men in the United States.

Many people do not realize men have breast tissue and can develop breast cancer. Men's breast tissue contains ducts. Like all cells of the body, a man's breast duct cells can undergo cancerous changes. Although certain risk factors may increase a man's chances of developing breast cancer, the cause of most breast cancers in men is unknown.

Most of the information about treating male breast cancer comes from doctors' experience with treating female breast cancer. The prognoses for men with breast cancer are similar to that of women with the disease. There are too few men with breast cancer for doctors to study in clinical trials.

Stages of Male Breast Cancer

Stage 0: The earliest form of breast cancer where cancer cells are located within a duct and have not invaded the surrounding fatty breast tissue. 

Stage I: The tumor is 2 cm (about 4/5 of an inch) or less in diameter.  The cancer has not spread outside the breast. 

Stage II: Cancer has not spread to distant sites, but is:

• larger than 2 cm in diameter and less than 5 cm and has spread to one to three axillary lymph nodes; or
• the tumor is larger than 5 cm and does not grow into the chest wall and has not spread to lymph nodes.

Stage III: Cancer has not spread to distant sites, but is:

• smaller than 5 cm in diameter and has spread to 4 to 9 axillary lymph nodes; or
• the tumor is larger than 5 cm and has spread to 1 to 9 axillary nodes or to internal mammary nodes; or
• the tumor has grown into the chest wall or skin and may have spread to no lymph nodes; or
• the tumor is any size, has spread to 10 or more nodes in the axilla or to one or more lymph nodes under the clavicle (infraclavicular) or above the clavicle (supraclavicular) or to internal mammary lymph nodes.

Stage IV: The cancer, regardless of its size, has spread to distant organs such as bone, liver, or lung, or to lymph nodes far from the breast.