What is the most common Breast Cancer?

Ductal Carcinoma is the most common type of breast cancer.  There are two types:  Ductal Carcinoma In Situ (DCIS)which is considered a pre-malignancy of the breast and there is Invasive Ductal Carcinoma of the breast.

The ducts refer to milk ducts.  This type of cancer comes from the lining of a milk duct within the breast.  These ducts carry milk from the lobules where the milk is made.