Breast cancer is the most common cancer among women, other than skin cancer. It is the second leading cause of cancer death in women, after lung cancer.
An estimated 211,240 women in the United States will be found to have invasive breast cancer in 2005, and predictions are that about 40,410 women will die from the disease this year. Right now there are slightly over 2 million women living in the US who have been treated for breast cancer.
The chance of a woman having invasive breast cancer some time during her life is about 1 in 7. The chance of dying from breast cancer is about 1 in 33. Breast cancer death rates are going down. This decline is probably the result of earlier detection and improved treatment.
What is cancer?
The body is made up of various kinds of cells, which normally divide in an orderly way to produce more cells only when they are needed. Cancer is a group of diseases - more than 100 types - that occur when cells become abnormal and divide without control or order.
What is a tumor?
When cells divide at times when new cells are not needed, too much tissue is formed. This mass of extra tissue, called a tumor, can be benign or malignant.
Benign tumors:
- are not cancerous;
- can usually be removed;
- do not come back in most cases;
- do not spread to other parts of the body and the cells do not invade other tissues
Malignant tumors:
- ◦are cancerous;
- ◦can invade and damage nearby tissues and organs;
◦and can metastasize. (Cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system to form secondary tumors in other parts of the body.)
What is Breast Cancer?
Breast cancer is a malignant (cancerous) tumor that starts from cells of the breast. The disease occurs mostly in women, but men can get breast cancer as well.
A woman’s breast is made up of lobules (glands that make breast milk), ducts (small tubes that connect lobules to the nipple), fatty and connective tissue, blood vessels, and lymph vessels. Most breast cancers begin in the ducts (ductal carcinoma), some in the lobules (lobular carcinoma), and the rest in other tissues.
Lymph vessels are like veins, except that they carry lymph fluid instead of blood. Lymph is a clear fluid that contains immune system cells and waste products. Lymph vessels lead to small, bean-shaped collections of tissue called lymph nodes. Most lymph vessels of the breast lead to lymph nodes under the arm. These are called axillary nodes. If a breast cancer spreads, often the first locations to which it spreads are the nearby lymph nodes.
Types of breast cancer
The major categories of breast cancer are:
Breast cancer in men is much less common with the average man having a less than one-percent lifetime risk of developing breast cancer. Men who have known family gene mutations or a BRCA 2 gene mutation are at increased risk for developing breast cancer. Men should be aware of breast cancer and be screened appropriately. (Jefferson’s Hereditary Cancer Program is dedicated to identifying individuals of a known or suspected inherited predisposition to cancer, and helping these patients to manage their risk.)
