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 .
In the past, LCIS was not considered to be a precursor (a condition that can develop into) to breast cancer. However, recent evidence shows some LCIS may develop into invasive lobular cancer [147-149].
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 [89-90]:
This medical care helps ensure that if cancer does develop, it is caught early when the chances of survival are highest.
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 try to lower their risk of breast cancer . Tamoxifen and raloxifene are the only two drugs FDA-approved for breast cancer prevention.
Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive breast cancers. Neither drug reduces the risk of estrogen receptor-negative cancers .
Both tamoxifen and raloxifene can lower the risk of :
Both pre- and postmenopausal women with LCIS can take tamoxifen . Raloxifene is only for use among postmenopausal women.
Raloxifene is slightly less effective than tamoxifen in reducing the risk of invasive breast cancer . However, 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.
The hormone drugs aromatase inhibitors are part of standard treatment for estrogen receptor-positive breast cancer in postmenopausal women (learn more). These drugs are now being studied to see whether they lower the risk of breast cancer in postmenopausal women at higher risk, including women with LCIS.
The hormone drugs aromatase inhibitors are part of standard treatment for breast cancer in postmenopausal women (learn more). These drugs are now being studied to see whether they lower the risk of breast cancer in postmenopausal women at higher risk, including women with LCIS.
Findings from a recent randomized controlled trial showed the aromatase inhibitor exemestane (Aromasin) lowered the risk of breast cancer in postmenopausal women at higher risk (learn more) .
Although exemestane is FDA-approved for use in breast cancer treatment, it does not yet have FDA-approval for use as a risk-lowering drug.
Learn about emerging areas in risk-lowering drugs for women at higher risk of breast cancer.
Learn about exemestane and other aromatase inhibitors and breast cancer treatment.
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 recommended breast cancer screening) over prophylactic bilateral mastectomy. Talk to your health care provider about the risks and benefits of these options so you choose the one that is best for you.
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.
Komen Support Resources
- Our breast care helpline 1-877 GO KOMEN (1-877-465-6636) provides free, professional support services and help finding local support groups. Our trained and caring staff are available to you and your family Monday through Friday from 9:00 a.m. to 10:00 p.m. EST and from 6:00 a.m. to 7:00 p.m. PST.
- Our Message Boards offer online forums to share your thoughts or feelings about subjects related to breast cancer. Our Women at Higher Risk of Breast Cancer forum within the Message Boards offers women at higher risk a place to share their own unique experiences and challenges.