Breast cancer is the most common type of cancer in women, it accounts for one of every three diagnoses in the United States. Breast cancers are malignancies, life threatening tumors that develops in one or both breasts.
A female breast consists of fatty and fibrous connective tissues. The interior of the breast is divided into about twenty different sections called lobes. Each of the lobes is further divided in to lobules, which are structures that contain small milk-producing glands. These glands place the milk into tiny ducts. These ducts take the milk through out the breast and store in a chamber located below the nipple.
Breast cancer can either be invasive (spreading) or noninvasive (non-spreading). An invasive cancer penetrates the wall of a duct. This type of cancer is the most common, constituting about seventy percent of all cases. Infiltrating lobular cancer that spreads through a wall of a lobule accounts for about eight percent of all breast cancer. This type is likely to appear in both of the breast, often in seven separate locations.
The cause of breast cancer is unknown but researchers are suggesting that estrogen, a hormone produced by the ovaries, may be involved. Studied suggest that the longer a women is exposed to the hormone (i.e. If she starts to menstruate before the age of twelve or if she went through menopause after the age of fifty-five and/or had children after the age of thirty) are at a greater risk.
Recently two breast cancer susceptibility genes have been identified. The first one is BRCA1 (a flaw in this gene is common to those who have breast cancer) and the second is BRCA2 (a defect in this gene is associated with breast cancer alone). People who have a mutated BRCA1 gene have an eighty-six percent risk of developing breast cancer by the age of seventy.
Women are one hundred times more likely to get breast cancer than men. More than eighty percent of breast cancer occur in women over the age of fifty. At the age of forty her odds are one in two hundred and seventeen (217), and in women younger than thirty they account for only one and a half percent of all breast cancer cases. About five percent of all breast cancers are inherited. Those with a family history of breast cancer in a first-degree relative (i.e. mother, sister, and daughter) are two to three times the risk of the general population.
Women who take hormone replacement therapy for more than five years may also have an increased risk. This is because the therapy causes the density of the breast tissue to increase and mammograms may miss some sign of the cancer.
Chemicals are also suspected to cause breast cancer. Xenoestrogens are chemicals with estrogen-like effects, they are found in pesticides and other common industrial products. Other estrogen-like chemicals that have a stronger association with breast cancer include dieldrin and beta-hexachloraocyclohexane. Although these chemicals are very weak estrogens, one study showed that exposure...