Breast cancer

Encyclopedia of Medicine, Apr 06, 2001 by Carol A. Turkington

Breast cancer is the abnormal growth and uncontrolled division of cells in the breast. Cancer cells can invade and destroy surrounding normal tissue, and can spread throughout the body via blood or lymph fluid (clear fluid bathing body cells) to start a new cancer in another part of the body.

Every woman is at risk for breast cancer. If she lives to be 85, there is a one out of nine chance that she will develop the condition sometime during the rest of her life. As a woman ages, her risk of developing breast cancer rises dramatically regardless of her family history. The breast cancer risk of a 25-year-old woman is only one out of 19,608; by age 45, it is one in 93. In fact, 80% of all breast cancers are found in women over age 50.

There are a number of risk factors for the development of breast cancer, including:

• Family history of breast cancer in mother or sister
• Early onset of menstruation and late menopause
• Reproductive history: women who had no children or have children late in life and women who have never breastfed have increased risk
• History of abnormal breast biopsies.

However, more than 70% of women who get breast cancer have no known risk factors. While a breast cancer gene was discovered in 1994, only about 5% of breast cancers are believed to be related to the gene.

In addition, some studies suggest that high fat diets, bottle feeding instead of breastfeeding, or using alcohol may contribute to the risk profile. Some studies have also found that for certain women, hormone replacement therapy may contribute to the development of breast cancer. However, these findings have been criticized.

It is important to realize that not all lumps detected in the breast are cancerous. Many are benign and require only the removal of the lump. While having several risk factors may boost a woman's chances of having breast cancer, the interplay of factors is complex. The best way to assess breast cancer risk is by doing monthly self examinations to detect any lump at an early stage. The second is to have a regular mammogram, an x ray of the front and side of the breast that will detect cysts or tumors at the earliest possible stage. Seeking risk assessment consultation at one of the many breast cancer centers located throughout the United States is also helpful.

The changes in the breast that may be a sign of breast cancer include:

• Lump or thickening in breast or armpit
• Changes in a nipple (thickening, pulling in, bleeding or discharge)
• Dimpled or reddened skin over the breast
• Change in size or shape
• Abnormality on a mammogram.

More than 90% of all breast cancers are detected by mammogram (a low-dose x ray of the breast). Mammograms should be done to evaluate a suspicious lump. Screening mammograms should be ordered according to the doctor's guidelines. Despite the controversy about the cost-effectiveness of mammograms for women in their 40s, most doctors agree with the current American Cancer Society guidelines that recommend screening mammograms every year or two for women between 40 and 49, and every year after age 50. Women with a family history of breast cancer may want to have a mammogram every year after age 40.

A typical mammography screening includes two views of each breast (one from above, and one from the side). Normally, the technician examines the x-ray pictures immediately to make sure no further x rays are needed, or to decide whether an ultrasound may be required.

If anything irregular is detected, such as a mass, changes from earlier mammograms, abnormalities of the skin, or enlargement of the lymph nodes, further testing may be recommended. This could include an ultrasound of the breast, a biopsy or needle sampling, or consultation with a breast surgeon.

Biopsy of the breast is a removal of breast tissue for examination by a pathologist. An excisional biopsy is a surgical procedure in which the entire lump area and some surrounding tissue is removed for examination. If the mass is very large, an incisional biopsy is done where only a portion of the area is removed and analysed. Needle biopsy can be done in two methods. An aspiration needle biopsy uses a very fine needle to withdraw cells and fluid from the mass for analysis. A large core needle biopsy uses a larger diameter needle to remove small pieces of tissue from the mass that can be analyzed. These analyses can determine whether the mass is benign (non-cancerous) or cancerous and therefore, whether further treatment is required.

To find out if the cancer has spread to other parts of the body (metastasized), doctors remove some underarm lymph nodes to test for cancer cells that have spread and to assist in making decisions for treatment. Checking to see if there are cancer cells in the lymph nodes is also a way to tell how advanced the cancer is ("staging" cancer). Breast cancer is rated from Stage 0 to Stage IV. Staging uses the diagnostic information to tell the cancer physician (oncologist) how widespread the disease is and includes: