Also referred to as carcinoma in situ or stage 0 cancer, a non-invasive breast cancer originates in the breast’s milk lobules or ducts and stays there. In other words, the cancer cells would not invade or grow into normal tissues beyond or within the breast if they are addressed in time. This cancer variant is essentially an early type of breast cancer, and is at times referred to as ‘pre-cancerous’. 

Non-invasive breast cancer, as aforementioned, could begin in the ducts or lobules and there is a different medical name for each. If the cancer occurs in the milk ducts, it’s called ductal carcinoma in situ (DCIS). If it happens in the milk lobules, it’s referred to as lobular carcinoma in situ (LCIS). DCIS is an early and treatable form of non-invasive cancer, and is also the most common non-invasive breast cancer type. However, if left untreated for long, this non-invasive breast cancer type may transform into the invasive type. LCIS, on the other hand, is technically not cancer, but its presence indicates an increased risk of the patient developing breast cancer in the future.


The treatment entails removing the affected tissue to ensure there are zero cancer cells remaining in the breast. For this, a surgery such as lumpectomy or mastectomy could be performed, which could then be followed by radiation therapy. Surgeries could also be performed to conserve the breast. To reduce the possibility of invasive breast cancer developing, some women could choose to remove their breast(s) through a surgery known as prophylactic mastectomy.