Lobular Carcinoma in Situ (LCIS)

Lobular carcinoma in situ (LCIS) may also be called lobular neoplasia. In this breast change, cells that look like cancer cells are growing in the milk-producing glands of the breast (called the lobules), but they don’t grow through the wall of the lobules.

LCIS is not considered to be cancer, and it typically does not spread beyond the lobule (become invasive breast cancer) if it isn’t treated. But having LCIS does increase your risk of developing an invasive breast cancer in either breast later on, so close follow-up is important.

Diagnosis

LCIS is diagnosed by a biopsy. (Breast tissue is removed and checked in the lab.) Often, LCIS does not cause a lump that can be felt or changes that can be seen on a mammogram. In most cases, LCIS is found when a biopsy is done for another breast problem that’s nearby.

You can learn more about pathology reports showing LCIS in Understanding Your Pathology Report: Lobular Carcinoma In Situ.

How does LCIS affect breast cancer risk?

Women with LCIS have about a 7 to 12 times higher risk of developing invasive cancer in either breast. For this reason, women with LCIS should make sure they have regular breast cancer screening tests and follow-up visits with a health care provider for the rest of their lives.

Treatment

In most cases, LCIS does not need to be treated. Sometimes if LCIS is found using a needle biopsy, the doctor might recommend that it be removed completely (with an excisional biopsy or some other type of breast-conserving surgery) to help make sure that LCIS was the only thing there. This is especially true if the LCIS is described as pleomorphic or if it has necrosis (areas of dead cells), in which case it might be more likely to grow quickly.

Reducing breast cancer risk or finding it early

Women with LCIS are at higher risk for breast cancer, so close follow-up is very important. Close follow-up of both breasts is important because women with LCIS have the same increased risk of developing cancer in both breasts. Women should also talk to a health care provider about what they can do to help reduce their breast cancer risk. Options for women at high risk of breast cancer because of LCIS may include:

• Seeing a health care provider more often (such as every 6 to 12 months) for a breast exam along with the yearly mammogram. Additional imaging with breast MRI may also be recommended.
• Making lifestyle changes to lower breast cancer risk. To learn more, see Can I Lower My Risk of Breast Cancer?  
• Taking medicine to help lower the risk of breast cancer. For more on this, see Deciding Whether to Use Medicine to Reduce Breast Cancer Risk.
• Surgery, called bilateral prophylactic mastectomy (removal of both breasts), to reduce risk. This may be followed by delayed breast reconstruction.