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A woman has a 12 percent chance of developing invasive breast cancer in the course of her lifetime. The American Cancer Society estimates about 230,480 new cases of invasive and approximately 57,650 new cases of noninvasive breast cancer will be diagnosed in the United States during 2011. The types of breast cancer are categorized by location and characteristics.
Ductal Carcinoma In-situ (DCIS)
This is the most common type of noninvasive breast cancer. As the name implies, the cancerous cells are confined to the lining of the ducts which are responsible for breast milk production. The abnormal cells have not spread through the duct wall into surrounding breast tissue. DCIS is referred to as stage 0 cancer.
Infiltrating Ductal Carcinoma (IDC)
This type of breast cancer accounts for 78 percent of all malignancies. The abnormal cells have invaded to surrounding tissue, including the lymph nodes. These lesions appear as star-like or rounded masses on mammograms. Generally, these stellate lesions of IDC have a poorer prognosis. Stage 2, 3 and 4 breast cancers are IDC.
This is a rare subtype of invasive ductal carcinoma. It accounts for 15 percent of all breast cancer types. Though it can occur at any age, medullary carcinoma usually affects women in their late 40s and 50s. This type of cancer gets its name because it resembles the part of the brain called the medulla oblongata.
Infiltrating Lobular Carcinoma (ILC)
This is the second most common type of invasive breast cancer and accounts for about 10 to 15 percent of all cases of breast cancer. It begins in a duct or lobule and spreads to surrounding breast tissue. ILC usually appears as a thickening in the upper outer quadrant of the breast. It usually affects women between the ages of 45 and 56 years of age.
This is a rare subtype of invasive ductal carcinoma. It accounts for about 1 to 2 percent of all breast cancer cases. When examined under a microscope, the tubular carcinoma cells have a distinctive tubular structure. The average age of diagnosis is from the mid-40s to the late 60s.