Unknown: Breast Cancer
Unknown: Breast Cancer
Breast cancer is cancer that starts in the tissues of the human breast. It is the second most common cancer in women, but can also affect men. There are two main types of breast cancer. The more common of the two, ductal carcinoma, begins in the ducts, or tubes, that carry milk from the interior of the breast to the nipple. The other major type is lobular carcinoma. It begins in the lobules, which are the parts of the breast that secrete milk.
Breast cancer is one of the most feared cancers for women, not only because it is potentially fatal but also because it can lead to disfigurement and worries about the loss of femininity. It can also develop for a long time before obvious symptoms appear. One reason why periodic screening for changes in breast tissue is so important for women over the age of twenty is that breast cancer is highly treatable when caught early.
In the early stages of breast cancer, a woman (or man) may not notice any differences in the size and shape of the breasts. The most noticeable symptom of breast cancer is a lump or thickened area in the breast. Not all such lumps are cancerous; many women notice that the texture of their breasts changes during pregnancy or their menstrual periods. Lumps in the breast can also be caused by noncancerous cysts. Nonetheless, a woman (or man) who notices a lump in the breast should tell their doctor.
Breast cancer is one of the most common cancers in women, affecting one in every eight women in the United States in the course of her lifetime. According to the American Cancer Society, there are about
68,000 cases of carcinoma in situ (noninvasive or stage 0 breast cancer) in the United States each year, and 183,000 cases of invasive breast cancer (stages I through IV). About 2,000 American men will be diagnosed with breast cancer.
Breast cancer is the second leading cause of death from cancer among women in the United States; only lung cancer is deadlier. About 41,000 American women and 450 men die each year from breast cancer. The death rate has decreased in recent years, largely as a result of earlier detection. There were an estimated 2.5 million survivors of breast cancer in the United States as of 2008.
Risk factors for breast cancer include:
Breast Cancer in Men
Most men think of breast cancer as a disease that affects only women. About one percent of all breast cancers, however, occur in men. About 2,000 men in the United States are diagnosed with breast cancer in an average year and 450 will die from it. Breast cancer is most likely to strike men between the ages of sixty and seventy; the average age at the time of diagnosis is sixty-seven. Men who are most at risk are those with a family history of breast cancer, a mutation in the BRCA2 gene, Kline-felter syndrome, liver disease, exposure to radiation therapy for prostate cancer, obesity, or a history of heavy drinking.
The symptoms, diagnostic tests, staging, and treatment for male breast cancer are similar to those for women. Men have a higher risk of breast cancer spreading to the bones or lungs than women do, however, so early diagnosis and treatment is critical.
- Sex. The female/male ratio for breast cancer is 99:1.
- Age. Two out of three invasive breast cancers are found in women over fifty-five.
- Genetic mutations. Between 5 and 10 percent of breast cancers are thought to be caused by inherited mutations in two genes known as BRCA1 and BRCA2. Women with either of these mutations have an 80 percent chance of developing breast cancer in their lifetime.
- Family history of breast cancer. A woman who has a mother, sister, or daughter with breast cancer has double the risk of developing breast cancer herself.
- Race. Caucasian women are slightly more likely to develop breast cancer than women of other races; however, breast cancers in African American women are often more aggressive. The reason for this difference is not known.
- Early menstruation (before age twelve) or late menopause (after age fifty-five).
- First pregnancy after age thirty or no pregnancy.
- Exposure to radiation during adolescence.
- Use of birth control pills or hormone replacement therapy after menopause.
- Heavy drinking.
- History of precancerous changes in the breast.
Causes and Symptoms
The cause of breast cancer is not known. Most researchers think that the disease results from a combination of genetic factors and environmental influences.
Breast cancer has no symptoms in its earliest stages. The first noticeable symptoms may include:
- A lump or thickened area in the breast large enough to be felt during a breast self-examination.
- A watery, bloody, or yellowish discharge from the nipple.
- A change in the shape or size of the breast.
- A flattened, puckered, or indented area in the skin of the breast.
- An orange-peel appearance to the skin of the breast.
Regular screening for breast cancer is important. All women over twenty should learn to perform breast self-examination and check their breasts once a month after the menstrual period. Other screening tests include a breast examination by the doctor as part of a routine office visit, and a mammogram, which is an x-ray study of the breast. Imaging studies (magnetic resonance imaging [MRI] or ultrasound) are done when a mammogram yields abnormal findings.
The definitive test for diagnosing breast cancer is a biopsy. The doctor may remove some tissue through a fine needle (aspiration biopsy) or if a larger sample is needed, through a larger needle (core biopsy). The most accurate technique is a surgical biopsy, in which the surgeon removes all or part of a lump for examination under a microscope.
The first step in treating any kind of cancer is staging. Staging is a description of the location of the cancer, its size, how far it has penetrated
into healthy tissue, and whether it has spread to other parts of the body. Breast cancer is classified into five stages:
- Stage 0: The cancer is in a lobule or a duct but has not spread beyond it. Breast cancer in this stage is called carcinoma in situ. This type of breast cancer is considered noninvasive.
- Stage I: The cancer is no more than three-quarters of an inch across and has not spread beyond the breast.
- Stage II. The cancer is between three-quarters and two inches across and may have spread to the lymph nodes under the arm.
- Stage III. The cancer has grown into the chest wall or the skin of the breast, is larger than two inches across, and has spread to lymph nodes behind the breastbone and under the arm.
- Stage IV. The cancer has spread to other parts of the body.
Surgery is usually the first line of treatment for breast cancer. Complete removal of the breast and underlying chest muscle, called a radical mastectomy, while more common in the past, is now rarely performed. Surgeons are more likely to recommend one type or another of breast-sparing surgery:
- Lumpectomy. In this type of surgery, the surgeon removes the cancer itself and a small amount of tissue around it.
- Partial mastectomy. The surgeon removes the cancer, the breast tissue surrounding it, and some of the underlying muscle.
- Simple mastectomy. The surgeon removes the entire breast.
- Modified radical mastectomy. The surgeon removes the entire breast and nearby lymph nodes but leaves the chest muscles in place.
- Reconstruction. Many women have plastic surgery at the same time as a mastectomy or as a later operation to restore the shape of the original breast. The surgeon may use an artificial implant or the patient's own tissue to reconstruct the breast.
Other treatments for breast cancer that may be used after surgery include:
- Radiation therapy. The radiation may come from a large machine outside the body or from implanted plastic tubes containing a radioactive substance. The tubes remain in place for several days and are removed before the patient leaves the hospital.
- Hormone therapy. This approach to treatment involves taking drugs by mouth to block the production of estrogen and other female hormones. Estrogen encourages the growth of some breast cancers, and hormone blockers are effective in slowing these tumors in some patients.
- Biological therapy. Also called targeted therapy, this approach stimulates the body's immune system to fight cancer cells rather than attacking them directly. It can also be used to control side effects from chemotherapy and radiation therapy, which often include nausea, vomiting, hair loss, and fatigue.
The prognosis for breast cancer depends on its stage at the time of diagnosis and the number of lymph nodes that were involved when the cancer was discovered. Women whose tumors were smaller than three-quarters of an inch with no lymph node involvement have a survival rate of 96 percent five years after diagnosis; those with tumors larger than two inches with several lymph nodes involved have a five-year survival rate of only 45 percent.
There are no guarantees that a specific woman will not get breast cancer, but there are some steps women can take to reduce their risk:
- Genetic testing. Women with a family history of breast cancer can get tested for a mutation in the BRCA gene. They can then consult their doctor about their own risk of developing breast cancer.
- Taking drugs that have been shown to reduce the risk of breast cancer. These include tamoxifen and raloxifene.
- Preventive mastectomy. Surgical removal of both breasts before cancer can develop is a treatment sometimes undertaken by women who are at very high risk of breast cancer or who have been diagnosed with a lobular carcinoma in situ.
- Surgical removal of the ovaries. Since the ovaries are the main source of estrogen in a woman's body, this type of operation is sometimes recommended for women with a known BRCA mutation.
Other preventive measures recommended by the American Cancer Society include getting regular exercise, limiting alcohol intake, keeping
weight at a healthy level, and avoiding the use of hormone replacement therapy after menopause.
Researchers are investigating different types or combinations of hormone therapy as a treatment for breast cancer. One large clinical trial is known as the Study of Tamoxifen And Raloxifene or STAR trial. Other research involves new diagnostic techniques for catching breast cancer early.
SEE ALSO Alcoholism; Klinefelter syndrome; Obesity; Prostate cancer
WORDS TO KNOW
Biological therapy: An approach to cancer treatment that is intended to strengthen the patient's own immune system rather than attack the cancer cells directly.
Carcinoma in situ: A cancer that has not spread or is still in one location in the body.
Lobule: One of the glands in the breast that produce milk.
Mastectomy: Surgical removal of the breast.
Staging: Measuring the severity or spread of a cancer.
American Cancer Society. Breast Cancer Clear and Simple: All Your Questions Answered / from the Experts at the American Cancer Society. Atlanta, GA: American Cancer Society Health Promotions, 2008.
Brown, Zora K., and Karl Boatman. 100 Questions and Answers about Breast Cancer. Sudbury, MA: Jones and Bartlett Publishers, 2009.
Willis, Jack. Saving Jack: A Man's Struggle with Breast Cancer. Norman, OK: University of Oklahoma Press, 2008.
Harmon, Amy, Alissa Krimsky, and Kassie Bracken. “Preparing for the Worst, Hoping for the Best.” New York Times, September 2007. Available online at http://video.on.nytimes.com/?fr_story=0aff7eb1147f98a41e989541f3fc114c8e71dcd2 (accessed on September 23, 2008). This is an online video about a “previvor,” a young woman who chose to have a preventive mastectomy when she learned she has a high risk of developing breast cancer. It takes about six and a half minutes to play.
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Mayo Clinic. Breast Cancer. Available online at http://www.mayoclinic.com/health/breast-cancer/DS00328 (updated September 26, 2007; accessed on September 23, 2008).
National Cancer Institute (NCI). What You Need to Know about Breast Cancer. Available online at http://www.cancer.gov/cancertopics/wyntk/breast/allpages (updated November 1, 2007; accessed on September 23, 2008).
National Library of Medicine (NLM). Breast Cancer. Available online at http://www.nlm.nih.gov/medlineplus/tutorials/breastcancer/htm/index.htm (accessed on September 23, 2008). This is an online tutorial with voiceover; viewers have the option of a self-playing version, an interactive version with questions, or a text version.