Breast cancer, a cancer that forms from the ducts, lobules or nipple of the breast, is an extremely prevalent disease. The National Cancer Institute reports that almost 195,000 new cases of breast cancer were diagnosed in the United States in 2009, and that breast cancer caused over 40,000 deaths. Cancer is staged according to the size and invasiveness of a tumor, and womenshealth.gov reports that breast cancer is considered in the beginning stages if has not metastasized and spread to distant parts of the body.
Initiation of Tumor Growth
The first stage of breast cancer development occurs when breast cancer cells begin to develop a small tumor. This mass of cells can sometimes develop within the lobules, the structures that produce milk-called lobular carcinoma, or within the nipple. It most commonly occurs in the ducts, the tubes that connect the lobules to the nipple. In this very early stage of breast cancer, a lump is may not be detected by a physical breast examination, but may be detectable on a mammogram. Detected early, breast cancer therapies can very effectively treat the tumor.
Development of Blood Vessels
Another early step in the development of breast cancer is the re-arrangement of blood vessels in the breast to supply more blood to the tumor, a process called angiogenesis. Increased blood supply is needed to provide nutrients, energy and oxygen to the cancer cells to support tumor growth-without the ability to promote angiogenesis, tumor growth is stunted. Once the breast cancer cells have an increased blood supply due to angiogenesis, the tumor grows larger, and can likely be detected as a lump during a physical breast examination and in a mammogram.
The ability to develop new blood vessels is a prognostic marker for breast cancer, according to BNet, a division of CBS Interactive. Cancers that have a low capacity for angiogenesis are associated with a better prognosis than breast cancers with a high capacity. Cancer therapeutics can be used to halt angiogenesis to treat breast cancer.
Invasion of Neighboring Tissue
Another beginning stage in breast cancer development is the invasion of neighboring tissue. Most mature and healthy cells have a very limited ability to migrate. Breast cancer cells have mutated and gained the ability to invade healthy breast tissue around the tumor. This allows for more tumor growth, and represents one of the last stages of early breast cancer.
In addition to infiltrating neighboring tissue, the cells can also migrate and invade the lymph nodes-a part of the lymphatic system that makes up part of the immune system. There are several lymph nodes around the breast, with several lymph nodes found in the armpit. Once the breast cancer cells begin to invade the lymph nodes, patients will commonly notice a lump in their armpit. If left undetected or untreated, the cancer will progress out of the beginning stages and metastasize to distant sites throughout the body.
