Overview

Ductal carcinoma in situ (DCIS) is the presence of abnormal cells inside a milk duct in the breast.

DCIS is considered the earliest form of breast cancer. DCIS is noninvasive, meaning it hasn't spread out of the milk duct and has a low risk of becoming invasive.

DCIS is usually found during a mammogram done as part of breast cancer screening or to investigate a breast lump.

While DCIS isn't an emergency, it does require an evaluation and a consideration of treatment options. Treatment may include breast-conserving surgery combined with radiation or surgery to remove all of the breast tissue. A clinical trial studying active monitoring as an alternative to surgery may be another option.