A type of breast cancer that starts in a milk duct of the breast.
Mammary ductal carcinoma (ductal carcinoma in situ) is an early stage that hasn't spread outside of the milk duct. In invasive ductal carcinoma, cancer cells have spread to other parts of breast tissue.
Mammary ductal carcinoma is usually detected during a routine mammogram. Most women with the condition have no symptoms.
Cancer staging is done by a doctor. Treatments might include medication, radiation, and surgery.