**4.1 Non-invasive breast cancer**

It's a malignancy that has not spread beyond the lobule or ducts in which it's found [8]. Ductal carcinoma in situ is an example of a kind of non-invasive breast cancer. Ductal carcinoma in situ develops when abnormal cells form inside the milk ducts but do not spread to nearby tissue or to the outside. The term "in situ" means "in place." Atypical cells may develop and mature into invasive breast cancer even if they have not spread beyond the lobules or ducts.
