Breast Cancer

Breast Cancer

Waht is Breast Cancer?
Breast cancer is a cancer that starts in the breast, usually in the inner lining of the milk ducts or lobules. There are different types of breast cancer, with different stages (spread), aggressiveness, and genetic makeup. With best treatment, 10-year disease-free survival varies from 98% to 10%. Treatment includes surgery, drugs (hormone therapy and chemotherapy), and radiation.
In the United States, there were 216,000 cases of invasive breast cancer and 40,000 deaths in 2004. Worldwide, breast cancer is the second most common type of cancer after lung cancer (10.4% of all cancer incidence, both sexes counted) and the fifth most common cause of cancer death.In 2004, breast cancer caused 519,000 deaths worldwide (7% of cancer deaths; almost 1% of all deaths).
Breast cancer is about 100 times as frequent among women as among men, but survival rates are equal in both sexes
Some breast cancers require the hormones estrogen and progesterone to grow, and have receptors for those hormones. Those cancers are treated with drugs that interfere with those hormones, usually tamoxifen, and with drugs that shut off the production of estrogen in the ovaries or elsewhere; this may damage the ovaries and end fertility. Low-risk, hormone-sensitive breast cancers may be treated with hormone therapy and radiation alone. Breast cancers without hormone receptors, or which have spread to the lymph nodes in the armpits, or which express certain genetic characeristics, are higher-risk, and are treated more aggressively. One standard regimen, popular in the U.S., is cycophosphamide plus doxorubicin (Adriomycin), known as CA; these drugs damage DNA in the cancer, but also in fast-growing normal cells where they cause serious side effects. Sometimes a taxane drug, such as docetaxel, is added, and the regime is then known as CAT; taxane attacks the microtubules in cancer cells. An equivalent treatment, popular in Europe, is cyclophosphamide, methotrexate, and fluorouracil (CMF).Monoclonal antibodies, such as trastuzumab, are used for cancer cells that have the HER2 mutation. Radiation is usually added to the surgical bed to control cancer cells that were missed by the surgery, which usually extends survival, although radiation exposure to the heart may cause damage and heart failure in the following years.

Causes

The primary risk factors that have been identified are sex,age, childbearing, hormones, a high-fat diet,alcohol intake, obesity, and environmental factors such as tobacco use, radiation^[26] and shiftwork.However, studies of environmental and lifestyle factors only attribute a small increase in breast cancer to each factor. Furthermore, these studies are not randomized, controlled trials, and so they may associate breast cancer with factors that don't actually cause breast cancer
No cause is known for 95% of breast cancer cases, while approximately 5% of new breast cancers are attributable to hereditary syndromes. In particular, carriers of the breast cancer susceptibility genes, BRCA1 and BRCA2, are at a 30-40% increased risk for breast and ovarian cancer, depending on in which portion of the protein the mutation occurs.

• 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. Having certain types of abnormal cells (atypical hyperplasia and lobular carcinoma in situ [LCIS]) increases the risk of breast cancer.
• Race: Breast cancer is diagnosed more often in Caucasian women than Latina, Asian, or African American women.
• No physical activity: Women who are physically inactive throughout life may have an increased risk of breast cancer. Being active may help decrease risk.
• Tamoxifen may interact unfavorably with certain antidepressants when used for prevention of breast cancer recurrence.
• Abortion-breast cancer hypothesis: Mainstream organizations such as the American Cancer Society and National Cancer Institute have concluded there is no link between induced abortion and breast cancer, although a minority of doctors continue to disagree.