Types of Breast Cancer Noninvasive Breast Cancers Invasive Breast Cancers

The female breast has two main components; glandular tissue (lobes and ducts) and connective tissue. The breast is divided into 15 to 20 lobes that radiate outwards from the nipple and contain clusters of milk-producing glands. The lobes are further divided into smaller compartments called lobules. Each cluster drains into a duct, which connects the lobules and the nipple. The breast is held together by fatty connective tissue, which provides support and contains nerves as well as blood and lymphatic vessels.

Adenocarcinoma is a general term that refers to a cancer that starts in glandular tissues anywhere in the body. The majority of breast cancers start in glandular tissue and therefore are classified as adenocarcinomas. Those that originate in lobules are known as lobular carcinoma and those that begin in ducts are ductal carcinomas. The term "noninvasive breast cancer" refers to adenocarcinomas that are confined to lobules or ducts. Another term used to describe these cancers is in situ. Invasive breast cancer refers to a carcinoma that has spread from lobules or ducts to fatty connective tissue.

Noninvasive Breast Cancers

Noninvasive forms of breast cancers are classified as ductal carcinoma in situ or lobular carcinoma in situ. Another form of breast cancer, Pagets's disease of the nipple, can be noninvasive or invasive.

Ductal carcinoma in situ (DCIS): Refers to cancer cells that are present in the duct that have not penetrated the duct walls into the surrounding tissue. This is the most common form of noninvasive breast cancer. It is also highly curable; nearly 100% of women diagnosed with this early form of cancer can be cured. A mammogram is the best method for detection of DCIS. It is treated with surgery or surgery plus radiation therapy. This type of cancer is also referred to as intraductal carcinoma.

Lobular carcinoma in situ (LCIS): LCIS is a very early type of breast cancer that develops within the lobules of the breast and does not penetrate through the wall of the lobules. Researchers think that LCIS cells almost never progress to invasive lobular cancer. However, having this type of cancer places a woman at increased risk of developing an invasive breast cancer later in life, in either breast. Women with this diagnosis should consult their physician to determine an appropriate screening program. This type of cancer is sometimes referred to as lobular neoplasia.

Paget's disease of the nipple: This is a rare form of breast cancer, accounting for just 1% of all breast cancer cases. It begins in the ducts and spreads to the skin of the nipple and areola. Symptoms may include crusted, scaly, red, or oozing skin of the affected area, as well burning or itching. Paget's disease can be associated with either in situ carcinoma or invasive breast carcinoma.

This website provides general information only. A physician should be contacted if you need any medical advice or if medical decisions need to be made.