There Are Lots of Big Words Thrown Around About Breast Cancer – What Do They Mean?
When talking to doctors about breast cancer, there are a lot of medical terms they use that aren't always readily understood. What's an infiltrating lobular carcinoma, or carcinoma in situ?
Here are some definitions for some of the terms that can help!
This is a term used to describe a cancer that begins in the lining layer (epithelial cells) of organs such as the breast. Nearly all breast cancers are carcinomas (either ductal carcinomas or lobular carcinomas).
An adenocarcinoma is a type of carcinoma that starts in glandular tissue (tissue that makes and secretes a substance). The ducts and lobules of the breast are glandular tissue (they make breast milk in women), so cancers starting in these areas are sometimes called adenocarcinomas.
Carcinoma in situ
This term is used for an early stage of cancer, when it is confined to the layer of cells where it began. In breast cancer, in situmeans that the abnormal cells remain confined to ducts (ductal carcinoma in situ, or DCIS). These cells have not grown into (invaded) deeper tissues in the breast or spread to other organs in the body. Ductal carcinoma in situ of the breast is sometimes referred to as non-invasive or pre-invasive breast cancer because it may develop into an invasive breast cancer if left untreated.
When cancer cells are confined to the lobules it is called lobular carcinoma in situ. This is not actually a true pre-invasive cancer because it does not turn into an invasive cancer if left untreated.
Invasive (infiltrating) carcinoma
An invasive cancer is one that has already grown beyond the layer of cells where it started (as opposed to carcinoma in situ). Most breast cancers are invasive carcinomas, either invasive ductal carcinoma or invasive lobular carcinoma.
Ductal carcinoma in situ (DCIS)
In DCIS (also known as intraductal carcinoma), cancer cells form in the breast ducts but do not grow through the walls of the ducts into the fatty tissue of the breast or spread outside the breast. DCIS accounts for about 1 in 10 cases of breast cancer in men. It is almost always curable with surgery.
Infiltrating (or invasive) ductal carcinoma (IDC)
This type of breast cancer breaks through the wall of the duct and grows through the fatty tissue of the breast. At this point, it can spread (metastasize) to other parts of the body. At least 8 out of 10 male breast cancers are IDCs (alone or mixed with other types of invasive or in situ breast cancer). Because the male breast is much smaller than the female breast, all male breast cancers start relatively close to the nipple, so they are more likely to spread to the nipple. This is different from Paget disease as described below.
Infiltrating (or invasive) lobular carcinoma (ILC)
This type of breast cancer starts in the breast lobules (collections of cells that, in women, produce breast milk) and grows into the fatty tissue of the breast. ILC is very rare in men, accounting for only about 2% of male breast cancers. This is because men do not usually have much lobular tissue.
Lobular carcinoma in situ (LCIS)
In LCIS, abnormal cells form in the lobules, but they do not grow into the fatty tissue of the breast or spread outside the breast. Although LCIS is sometimes grouped with DCIS as a type of non-invasive breast cancer, most breast specialists think it is a risk factor for developing breast cancer rather than a true non-invasive cancer. As with invasive lobular carcinoma, LCIS is very rare in men.
Paget disease of the nipple
This type of breast cancer starts in the breast ducts and spreads to the nipple. It may also spread to the areola (the dark circle around the nipple). The skin of the nipple usually appears crusted, scaly, and red, with areas of itching, oozing, burning, or bleeding. The fingertips can be used to detect a possible lump within the breast.
Paget disease may be associated with DCIS or with infiltrating ductal carcinoma. It accounts for about 1% of female breast cancers and a higher percentage of male breast cancers.
Inflammatory breast cancer
Inflammatory breast cancer is an aggressive, but rare type of breast cancer. It causes the breast to be swollen, red, warm and tender rather than forming a lump. It can be mistaken for an infection of the breast. This is very rare in men.
Get more information at Cancer.org.