Breast Cancer

Collections of cells that are growing abnormally or without control are called tumors. Tumors that do not have the ability to spread throughout the body may be referred to as “benign” and are not thought of as cancerous. Tumors that have the ability to grow into other tissues or spread to distant parts of the body are referred to as “malignant.” Malignant tumors within the breast are called “breast cancer”. Theoretically, any of the types of tissue in the breast can form a cancer, cancer cells are most likely to develop from either the ducts or the glands. These tumors may be referred to as “invasive ductal carcinoma” (cancer cells developing from ducts), or “invasive lobular carcinoma” (cancer cells developing from lobes).

Sometimes, precancerous cells may be found within breast tissue, and are referred to as ductal carcinoma in-situ (DCIS) or lobular carcinoma in-situ (LCIS). DCIS and LCIS are diseases in which cancerous cells are present within breast tissue, but are not able to spread or invade other tissues. DCIS represents about 20% of all breast cancers. Because DCIS cells may become capable of invading breast tissue, treatment for DCIS is usually recommended. In contrast, treatment is usually not needed for LCIS.