carcinoma [car-sin-O-ma]

a cancer that begins in the lining layer (epithelial cells) of organs. At least 80% of all cancers are carcinomas.

carcinoma in situ [car-sin-O-ma in sy-too]

an early stage of cancer in which the tumor is confined to the organ where it first developed. The disease has not invaded other parts of the organ or spread to distant parts of the body. Most in situ carcinomas are highly curable. See also carcinoma.


ductal carcinoma in situ [duck-tul car-sin-O-ma in sy-too]

also called DCIS and intraductal carcinoma. Cancer cells that start in the milk passages (ducts) but have not grown through the duct walls into the nearby tissue. This is a highly curable form of breast cancer that is treated with surgery, or surgery plus radiation therapy.


lobular carcinoma in situ [lob-yuh-lur car-sin-O-ma in sy-too]

also called LCIS. Although not a true cancer, it is sometimes listed as a non-invasive type of breast cancer. It starts within the milk-producing glands (lobules) of the breast but does not grow through the wall of the lobules. It does not become an invasive cancer very often, but having LCIS places a woman at somewhat higher risk of developing an invasive breast cancer later in life. Women need a yearly mammogram and clinical breast exam after LCIS. Women with LCIS might also want to ask their doctors about the benefits and limits of yearly screening with magnetic resonance imaging (MRI). See also clinical breast examination, invasive lobular carcinoma, magnetic resonance imaging (MRI), mammogram.