Glossary Term:


breast cancer



cancer that starts in the breast. The most common types of breast cancer are ductal carcinoma in situ, invasive ductal carcinoma, invasive lobular carcinoma, medullary carcinoma, and Paget disease of the nipple (see definitions under these headings). Lobular carcinoma in situ is sometimes listed as a non-invasive type of cancer, even though it is not a true cancer.