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 cancer.
The following is a 3D interactive model showing LCIS. The labels show a normal lobe and a lobe with LCIS.
Learn more about breast anatomy.
LCIS and breast cancer risk
Women with LCIS have an increased risk of invasive breast cancer [267-269].
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) [267-268].
Women diagnosed with LCIS have [267,270-271]:
- About a 10% chance of developing ductal carcinoma in situ (DCIS) or invasive breast cancer in 10 years
- About a 20% chance of developing DCIS or invasive breast cancer in 20 years
Women with LCIS can develop invasive lobular cancer or invasive ductal cancer [267-268].
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) [267,271-273].
Learn about invasive lobular cancer and other types of tumors.
Learn about other factors linked to the risk of breast cancer.
LCIS and breast cancer screening
- Have a clinical breast exam every 6-12 months
- Have a mammogram every year, starting at age 30
- Talk with a health care provider about screening with breast MRI every year, starting at age 25
This medical care helps make sure if breast cancer does develop, it’s caught early when the chances of survival are highest.
The NCCN recommends women with LCIS who have a less than 20% lifetime risk of invasive breast cancer get the same breast cancer screening as women at average risk.
Learn more about breast cancer screening recommendations for women at higher risk.
Risk-lowering options for women with LCIS who do not have breast cancer
Talk with your health care provider about the risks and benefits of your risk-lowering options to choose the one that’s right for you.
Risk-lowering drugs for women with LCIS
It’s strongly recommended women with LCIS take a risk-lowering drug (such as tamoxifen) 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)
Learn more about risk-lowering drugs.
For a summary of studies on tamoxifen and raloxifene, visit the Breast Cancer Research Studies section.
Preventive surgery (risk-reducing mastectomy)
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 since the risk reduction benefits from a risk-lowering drug and surgery are similar .
Learn more about options for people at higher risk.
Learn more about talking with your health care provider.
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