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Breast cancer is the most common type of cancer among women in the United States, other than skin cancer. The American Cancer Society estimates that more than 230,000 women were diagnosed with breast cancer in 2011. Although rare, men can also develop breast cancer; an estimated 2,100 men were diagnosed with the disease in 2011. Although breast cancer deaths have decreased steadily each year since 1990, nearly 40,000 Americans die of the disease each year.
WHAT IS BREAST CANCER?
Breast cancer is an abnormality of specific cells within the breast. Normally, cells divide and form new cells as the body needs them. When cells grow old, they die, and new cells replace them. Sometimes this orderly process goes awry; new cells form when they are not needed and old cells do not die when they should. The extra cells that result form a mass of tissue called a tumor. Tumors can be cancerous or noncancerous. Cancerous breast tumors have the capacity to spread to nearby tissues or distant organs. This spread occurs when breast cancer cells break away from the original tumor and enter the bloodstream or lymphatic system. The spread of cancer is called metastasis. When breast cancer metastasizes to another organ, a new tumor forms that has the same kind of abnormal cells found in the original tumor.
WHO IS AT RISK?
No one knows the exact cause of breast cancer, although research has shown that women with certain risk factors are more likely than others to develop the disease. The chance of getting breast cancer increases as you age. Women older than age 60 are at greatest risk; most cases of breast cancer occur in this age group. The disease is uncommon before menopause. A woman's risk of breast cancer is higher if her mother, father, sister or daughter has had breast cancer, especially if the disease was diagnosed before age 50. If you have a close relative who has had breast cancer, your doctor may recommend testing to determine if you carry genes that may increase your risk of developing the disease. In the United States, Caucasian women develop breast cancer more commonly than do women of other races or ethnic backgrounds.
Women who began menstruating before age 12 and those who experience menopause after age 55 are at increased risk for breast cancer. Not having children also increases a woman's risk of developing the disease. Long-term hormone replacement therapy increases breast cancer risk, as does being overweight or obese. Lack of physical activity also increases your risk of developing the disease. The National Cancer Institute reports that a woman's risk of breast cancer may increase with her level of alcohol consumption.
Other factors may contribute to your risk of developing breast cancer. Discuss your personal risk of the disease with your doctor, who may suggest ways to reduce your risk and recommend a screening plan that suits your situation.
SYMPTOMS
Breast cancer usually does not cause symptoms early in the course of the disease. Changes in your breasts, however, may signal the presence of a cancerous tumor. Look for painless lumps in your breasts or under your arms, and changes in the shape or appearance of your breasts, including your nipples. Discharge from your nipples or tenderness of the area may be a warning sign.
BREAST CANCER SCREENING
Detecting breast cancer early in the course of the disease increases the probability of achieving a cure. The National Cancer Institute recommends that all women have regular clinical breast examinations, in which your doctor checks your breasts for tumors. Many physicians also recommend monthly breast self examination. Mammograms, or x-rays of the breasts, are recommended every one to two years for women after age 40. If you are at high risk for breast cancer, your doctor may recommend beginning mammogram screening before age 40. Breast MRI, another form of diagnostic imaging, may be recommended if you are at high risk for developing breast cancer.
DIAGNOSIS
The only way to be certain whether a breast tumor is cancerous is to examine a sample of the tissue under a microscope. A breast biopsy is the procedure used to remove a sample of tissue from a suspected tumor. There are different types of biopsy procedures; your doctor will discuss these with you and review the risks and benefits of each.
The doctor who examines the breast tissue sample will determine whether the cells are cancerous and, if so, what type of breast cancer it is. The most common type of breast cancer is ductal carcinoma, which originates from cells lining the milk ducts. Another common type of breast cancer is lobular carcinoma, which arises from the milk-producing glands. Other types of breast cancer are uncommon.
TREATMENT AND PROGNOSIS
The choice of treatment for breast cancer depends primarily on the type of cancer, whether the disease has spread and the extent of spread. As with other cancers, the three major forms of treatment are surgery, radiation therapy and chemotherapy. Your doctor will discuss your treatment options with you; ultimately, it is your decision to choose what treatments you want to pursue. Roughly 90 percent of women diagnosed with breast cancer are alive five years after diagnosis. Among women with breast cancer that has not spread outside of the breast, five-year survival is 98 percent, according to the American Cancer Society.
