This type of breast cancer has broken through the wall of the duct and invaded the fatty tissue of the breast. At that point, it has the potential to metastasize, or spread, to other parts of the body through the lymphatic system (lymph nodes) and bloodstream. More information on types of breast can be found at the American Cancer Society’s Breast Cancer Resource Center at http://www3.cancer.org/cancerinfo/load_cont.asp?ct=5&st=wi