Ductal Carcinoma In Situ (DCIS)
Ductal Carcinoma in situ originates in the milk ducts of the breast, which are the tubes that carry breast milk to from the lobules to the nipple. DCIS occurs when epithelial tissue cells (cells that line the ducts) turn malignant, or cancerous. However, since the cancer is in situ, these cells are contained to the ducts, and therefore the cancer has not spread into the surrounding breast tissue. Because of this, the cancer currently cannot metastasize (spread) to the rest of the body via the blood or the lymphatic system, and is classified as pre-cancer, or stage zero cancer. However, stage zero cancer has the potential to become an invasive cancer by invading the basement membrane of the ducts, meaning that DCIS will most likely need to be treated.