Metastatic Breast Cancer
What is normal breast tissue and what happens to it during breast cancer?
Breast cancer usually begins in and around the breast tissue which can spread rapidly over time.
A normal female breast tissue is made up of glands and ducts mostly. These glands or ‘lobules’ secrete milk, which is carried through the ducts to the nipple. Apart from these glands, there are fat, connective tissue, lymph nodes and blood vessels in the breast. Here is how a normal breast tissue looks like (Figure 1).
When the cells in these tissues start to divide uncontrollably and abnormally, it may lead to cancer. Cancer can begin in the glands, ducts or in the lymph vessels in and around the skin of the breast, including armpits. At later stages, these cells can move out of its place of origin and invade the surrounding areas. This is when the cancer is called ‘metastatic’, ‘invasive’ or, ‘infiltrating’. Breast cancer is one of the most frequently diagnosed cancers in women worldwide accounting for about 24.2% of new incidences among all cancers in women annually.
Breast cancer can be of different types based on the site of origin, type of proteins expressed, or on the stage of disease. Based on stage of disease, breast cancer can be identified as to be at an early stage, locally advanced stage or at a ‘metastatic’ stage. Metastatic cancer, also called stage IV breast cancer is that which has spread outside the breast tissue to other parts of the body. During metastasis, cancer cells travel through the bloodstream and penetrate blood and lymph vessels to reach and lodge in distant organs such as, lungs, liver, bones or brain or any other organ. It is estimated that nearly 30% of women diagnosed with early stage breast cancer go on to develop metastatic disease.
ACS: American Cancer Society BSE: Breast self-examination CBE: Clinical Breast examination IV: Intravenous mBC: Metastatic breast cancer MRI scan: Magnetic resonance imaging scan NCCN: National Comprehensive Cancer Network VEGF: Vascular Endothelial Growth Factor
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