Terminology Challenges

The terminology used to describe DCIS is often inconsistent. Patients may find the variation among definitions confusing. Medical authorities and organizations have rationales for their choice of descriptive terms defining DCIS. Key points of commonality to reinforce:

• DCIS is by definition confined to the lactiferous ducts
• DCIS cells are abnormal and do have characteristics of cancer cells
• DCIS cells are non-invasive but may acquire the ability to invade other tissues

DCIS definitions:

• The National Cancer Institute (NCI) at the National Institute of Health (NIH) defines DCIS as "A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, DCIS may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive. Also called ductal carcinoma in situ and intraductal carcinoma."
• The American Cancer Society defines DCIS as " the cancer cells are inside the ducts but have not spread through the walls of the ducts into the surrounding breast tissue."
• Breastcancer.org defines DCIS as "the most common form of non-invasive breast cancer."
• Cleveland Clinic defines DCIS as "a breast cancer which can grow within the milk duct, but does not invade into the surrounding tissue and does not spread to distant organs."
• College of American Pathologists defines DCIS as "DCIS is characterized by pre-cancerous or early-stage cell abnormalities in the breast ducts."
• Merriam-Webster Medical Dictionary "any of a histologically variable group of precancerous growths or early carcinomas of the lactiferous ducts that have the potential of becoming invasive and spreading to other tissues".
• MayoClinic.com "Ductal carcinoma in situ (DCIS) is considered the earliest form of breast cancer."