Types Of Breast Cancer

Types of Breast Cancer

Where breast cancer develops defines its histological history, which is its classification based on what type of tissue the disease originates from.  Most breast cancers begin in milk-producing lobes or the milk-carrying ducts.   Breast cancers originating in the ducts are called ducal carcinomas, which include most breast cancer cases. Ducal carcinoma in situ (DCIS) is cancer confined to the duct.  Tumors confined to the lobes are known as lobular carcinoma (LCIS).  It is not considered to be cancer, but is a risk factor for developing cancer.  Close monitoring of patients diagnosed with LCSI will help early detection of breast cancer.

Breast cancer is also classified according if it is contained to a specific tissue type or site in the body.  Breast cancer confined only to the type of tissue it originates from is called noninvasive cancer.  Invasive breast cancer, also known as infiltrating cancer, extends to other breast tissue and areas beyond the breast.

More recently, genetic profiling technology and tumor markers have led to classification of cancer based upon molecular subtypes.  This type of classification relies upon estrogen and progesterone receptors (ER and PR) along with human epidermal growth factor receptor 2 (HER2).  Physicians select the method of treatment by noting the presence or absence of these tumor markers.  Different classifications of cancer require different types of treatment.