Lobular Carcinoma in Situ (LCIS)

• When to see a doctor

  • Make an appointment with your doctor if you notice a change in your breasts, such as a lump, an area of puckered or otherwise unusual skin, a thickened region under the skin, or nipple discharge.

  • Ask your doctor when you should consider breast cancer screening and how often it should be repeated. Most groups recommend considering routine breast cancer screening beginning in your forties. Talk with your doctor about what is right for you.

• Causes

  • It is not clear what causes LCIS. LCIS begins when cells in a milk-producing gland (lobule) of a breast develop genetic mutations that cause the cells to appear abnormal. The abnormal cells remain in the lobule and do not extend into, or invade, nearby breast tissue.

  • If LCIS is detected in a breast biopsy, it does not mean that you have cancer. However, having LCIS increases your risk of breast cancer and makes it more likely that you may develop invasive breast cancer.

  • The risk of breast cancer in women diagnosed with LCIS is thought to be approximately 20 percent. Put another way, for every one hundred women diagnosed with LCIS, twenty will be diagnosed with breast cancer and eighty will not be diagnosed with breast cancer. The risk of developing breast cancer for women in general is thought to be 12 percent. Put another way, for every one hundred women in the general population, twelve will be diagnosed with breast cancer.

  • Your risk of breast cancer is based on many factors. Talk to your doctor to better understand your risk of breast cancer.

• Lobular Carcinoma in Situ (LCIS)

  • Lobular carcinoma in situ (LCIS) is a type of breast change that is sometimes seen when a breast biopsy is done. In LCIS, cells that look like cancer cells are growing in the lining of the milk-producing glands (lobules) of the breast, but they do not invade through the wall of the lobules.

  • LCIS is not considered cancer, and it typically does not spread beyond the lobule (that is, it does not become invasive breast cancer) if it is not treated. However, having LCIS does increase your risk of later developing invasive breast cancer in either breast. (See "How does LCIS affect breast cancer risk?")

  • LCIS and another type of breast change (atypical lobular hyperplasia, or ALH) are types of lobular neoplasia. These are benign (non-cancerous) conditions, but they both increase your risk of breast cancer.