Lobular Carcinoma in Situ (LCIS)
What is lobular carcinoma in situ (LCIS)?
The lobules of the breast are small round sacs that produce milk for breastfeeding.
When abnormal cells grow inside the lobules, but have not spread to 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.
Image source: National Cancer Institute (www.cancer.gov)
Learn more about breast anatomy.
LCIS and breast cancer risk
LCIS increases the risk of invasive breast cancer.
Compared to women without LCIS, those with LCIS are 7-11 times more likely to develop invasive cancer in either breast (the breast with LCIS or the opposite breast) [246-247].
Women diagnosed with LCIS have an estimated :
- 11 percent chance of developing breast cancer in 10 years
- 20 percent chance of developing breast cancer in 20 years
In the past, LCIS was not considered to be a precursor (a condition that can develop into) to breast cancer. However, some studies show LCIS may develop into invasive lobular cancer (invasive breast cancer that begins in the lobules) [247,249-251].
Learn about invasive lobular cancer and other types of tumors.
LCIS and breast cancer screening
There are special breast cancer screening guidelines for women with LCIS.
It’s recommended women with LCIS :
- Have a clinical breast exam every 6-12 months
- Have a mammogram every year, starting at age 30 (3D mammography (breast tomosynthesis) may be considered)
- Talk with their health care providers about screening with breast MRI every year, starting at age 25
This medical care helps ensure if breast cancer does develop, it’s 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
Talk with your health care provider about the risks and benefits of your risk-lowering options to find the one that is right for you.
Tamoxifen and raloxifene
It’s strongly recommended women with LCIS take tamoxifen or raloxifene to lower their risk of breast cancer .
Both tamoxifen and raloxifene can lower the risk of :
- Invasive breast cancer
- Non-invasive breast cancers, such as ductal carcinoma in situ (DCIS)
Tamoxifen and raloxifene are the only drugs FDA-approved for breast cancer risk reduction.
Both pre- and postmenopausal women can take tamoxifen. Raloxifene is only for use among postmenopausal women.
Although raloxifene is slightly less effective than tamoxifen in reducing the risk of breast cancer, it has fewer harmful health effects . This makes raloxifene a better choice for some women.
For example, tamoxifen increases the risk of cataracts and cancer of the uterus, 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.
For a summary of studies on tamoxifen and raloxifene, visit the Breast Cancer Research Studies section.
Aromatase inhibitors are hormone therapy drugs that are part of standard treatment for estrogen receptor-positive breast cancer.
Findings from randomized controlled trials have shown the aromatase inhibitors exemestane and anastrozole may lower the risk of developing breast cancer in postmenopausal women at higher risk, including women with LCIS [252-253].
The American Society for Clinical Oncology (ASCO), the National Comprehensive Cancer Network (NCCN) and the U.S. Preventive Services Task Force list exemestane and anastrozole as risk-lowering drug options for postmenopausal women at higher risk of breast cancer.
However, these drugs do not have FDA-approval for use in the risk reduction setting. They are only FDA-approved for use in breast cancer treatment.
Learn about aromatase inhibitors and breast cancer treatment.
Preventive surgery (prophylactic mastectomy)
Today, the use of tamoxifen or raloxifene (along with recommended breast cancer screening to find breast cancer early if it develops) is the preferred option for lowering risk in women with LCIS .
In the past, prophylactic bilateral mastectomy (surgery to remove both breasts) was considered for women with LCIS to lower breast cancer risk as much as possible. This is now discouraged.
Learn more about options for women at higher risk.
Learn more about talking with your health care provider.
SUSAN G. KOMEN® SUPPORT RESOURCES