Literally meaning “in place,” the term “in situ” refers to a very early form of cancer.  In general, the term “in situ” is used to indicate that abnormal cancer cells are present but have not spread past the boundaries of tissues where they initially developed.   Lobular carcinoma in situ (LCIS) refers to a sharp increase in the number, appearance, and abnormal behavior of cells contained in the milk-producing lobules of the breast (found within the lobes).

Though categorized as a stage 0 breast cancer (the earliest stage), LCIS is not considered a cancer. Rather, it is “marker” (a signal) that breast cancer may develop. In fact, LCIS has recently been renamed lobular neoplasia to signify this belief.  Neoplasia is defined as an abnormal growth in the number of cells. Though LCIS is not considered a cancer, women who are diagnosed with LCIS (also called lobular neoplasia) are at a higher risk of developing breast cancer later in life.

According to the National Cancer Institute, a woman with LCIS has a 25% chance of developing some form of invasive cancer (either lobular, or more commonly, infiltrating ductal carcinoma) within her lifetime.

The number of women diagnosed with LCIS has increased in recent years, most likely due to more rigorous breast cancer screening and advances in mammography techniques.  Often, LCIS is encountered serendipitously (by chance) while a pathologist is examining tissue from a breast biopsy that was performed for another reason (for example, to examine an area of concern found by physical examination or with mammography).

Treating LCIS

Currently, the majority of women who have been diagnosed with LCIS do not receive treatment after biopsy.  Instead, they are closely monitored by physicians with frequent clinical breast exams and mammograms.  It is essential that women with LCIS examine their breasts carefully, once a month, and see a physician immediately if they notice any changes or abnormalities. 

CONTINUED

1 | 2 | Next >

Return to Breast Health Main Menu