What is lobular carcinoma in situ (LCIS)?
When abnormal cells grow inside the lobules of the breast, but have not spread to the nearby tissue or beyond, the condition is called lobular carcinoma in situ (LCIS). The term "in situ" means "in place." With LCIS, the abnormal cells are still "in place" inside the lobules. Although the term LCIS includes the word “carcinoma,” LCIS is not invasive breast cancer.
Learn more about the anatomy of the breast.
LCIS and breast cancer risk
LCIS increases the risk of invasive breast cancer. Compared to women without LCIS, those with LCIS are seven to 12 times more likely to develop invasive cancer in either breast . Women with LCIS can develop invasive lobular cancer or invasive ductal cancer .
LCIS has been considered a risk factor for breast cancer, but not a precursor (a condition that can develop into) to breast cancer. However, some LCIS may develop into invasive lobular cancer .
Learn about different types of tumors.
LCIS and breast cancer screening
There are special breast cancer screening guidelines for women with LCIS. If you have LCIS, the National Comprehensive Cancer Network and the American Cancer Society recommend that you [40-41]:
- Get a clinical breast exam every six to 12 months
- Get a mammogram every year
- Talk to your health care provider about getting an MRI every year in combination with clinical breast exam and mammogram
This medical care helps ensure that if cancer does develop, it is caught early when it is most treatable.
Learn more about breast cancer screening recommendations for women at higher risk.
Risk-lowering options for women with LCIS
Tamoxifen and raloxifene
Women with LCIS may consider taking tamoxifen or raloxifene to prevent the development of invasive breast cancer . Studies show tamoxifen reduces the risk of invasive and non-invasive breast cancer for both pre- and postmenopausal women with LCIS .
Raloxifene is only for use among postmenopausal women. Although raloxifene is slightly less effective than tamoxifen in reducing the risk of invasive breast cancer, it has fewer harmful health effects . This makes it a better choice for some women. For example, tamoxifen increases the risk of cancer of the uterus and cataracts, but raloxifene does not. Tamoxifen also increases the risk of blood clots in the lungs and large veins more than raloxifene .
Learn more about tamoxifen and raloxifene.
A more drastic option for lowering the risk of breast cancer is to have a prophylactic bilateral mastectomy. This surgery involves removing both breasts to try to keep cancer from developing. Because the use of tamoxifen or raloxifene is effective in greatly reducing risk, most women with LCIS choose one of these options (along with breast cancer screening) over prophylactic bilateral mastectomy.
Learn more about options for women at higher risk.
Find questions about LCIS for your health care provider.
Learn more about talking to your health care provider.