The majority of all breast cancers start in the ducts of the breast. However, the ductal system is not the only area of the breast where cancer can grow. At the inside end of the duct is a lobe. This is referred to as the lobular system, where the milk is produced. 10% to 15% of breast cancers get their start in the lobes of the breast. Before lobular carcinoma develops, it begins as lobular carcinoma in situ or LCIS.

By "in situ" we are referring to cancer cells that are present in a system, but have not yet spread outside of it. The term LCIS refers to an increase of abnormal cells in the lobes of the breast that produce milk.

Although the abnormal cells classified as LCIS could develop into cancer and are called Stage 0 cancer, it is not considered to be an actual cancer. Having it present in the breast means that cancer could develop over time. Because of this new way of thinking about LCIS, doctors have started to rename it "lobular neoplasia" which is in reference to the abnormal growth of the cells.

Since women with LCIS have a much higher risk of ending up with breast cancer they must be followed up closely. A lot of times a woman will find out she has LCIS because of a biopsy that was done for something unrelated to the LCIS. While LCIS has been reclassified as a "non-cancer" that is treated differently than Ductal Carcinoma in situ, it is still a worrisome condition. Women who have been diagnosed with this should talk over all their options with their breast specialist to make a well informed decision on what, if any treatment options to follow.

Women with LCIS will be followed up closely. The standard followup will be a regular mammogram and screening. It will also consist of monthly self exams and regular visits to a breast specialist. Most women receive no other treatment for LCIS. If they do notice changes in their breasts or any thing that appears to be abnormal, they should contact their doctor immediately.

Some women may choose to take tamoxifen and may possibly participate in the STAR clinical trial. The STAR trial compares the effects and preventative effectiveness of tamoxifen and raloxifene. Both drugs reduce the amounts of hormones in the breast tissue. These drugs are usually taken for a period of five years. Tamoxifen has shown in studies to reduce the occurrence of more advanced breast cancer by up to 49% in women that have had LCIS or that have additional risk factors for developing breast cancer. Those addition risks are having atypical hyperplasia, or a family member with the disease. Recent studies have shown raloxifene to be very effective in preventing breast cancer in post menopausal women.

Some women who have a high risk of developing breast cancer may choose to have a preventive mastectomy of both sides with reconstruction to prevent breast cancer from occurring. Women who have this procedure will have a much lower risk of developing the disease.