Non-Invasive or Invasive Breast Cancer?

The single most important factor in the personality of any breast cancer is whether it is non-invasive ("in situ," which means "in the same place") or invasive. Invasive cancer has spread outside the milk duct or milk-making glands and has grown into normal tissue inside the breast. Whether your cancer is non-invasive or invasive will determine your treatment choices and how you might respond to the treatments you receive.

Non-invasive (or "in situ") cancers confine themselves to the ducts or lobules and do not spread to the surrounding tissues in the breast or other parts of the body. They can, however, develop into or raise your risk for a more serious, invasive cancer.

Invasive (or infiltrating) cancers have started to break through normal breast tissue barriers and invade surrounding areas. Read a study that discusses treatments to lower your risk of developing an invasive cancer after DCIS. Much more serious than non-invasive cancers, invasive cancers can spread cancer to other parts of the body through the bloodstream and lymphatic system.

Normal Breast with an enlarged cross-section of normal duct

Breast profile:

A Ducts

B Lobules

C Dilated section of duct to hold milk

D Nipple

E Fat

F Pectoralis major muscle

G Chest wall/rib cage

Enlargement

A Normal duct cells

B Basement membrane

C Lumen (center of duct)

You can read more and see pictures of the different types of non-invasive and invasive breast cancers on these pages:

• Ductal Carcinoma In Situ (DCIS)
• Lobular Carcinoma In Situ (LCIS)
• Invasive Ductal Carcinoma (IDC)
• Invasive Lobular Carcinoma (ILC)