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Lobular carcinoma in situ (LCIS)

Find out what lobular carcinoma in situ is, how it is diagnosed and treated, and about follow up.

What LCIS is

Lobular carcinoma in situ (LCIS) means that cells inside some of the breast lobules have started to become abnormal. The lobules are glands that make breast milk. The abnormal cells are all contained within the inner lining of the lobules.

LCIS is also called lobular neoplasia. It might be found in both breasts.

Having LCIS means that you have an increased risk of getting invasive breast cancer in either breast in the future. Even so, most women with LCIS won't develop breast cancer. Men can develop LCIS but this is very rare.

Lobular carcinoma in situ (LCIS)

About LCIS

LCIS is more common in women who haven't had their menopause. About 710 people are diagnosed with LCIS each year in the United Kingdom. This includes about 5 men.

Diagnosing LCIS

LCIS doesn't usually show up on breast x-rays (mammograms), and it normally doesn't cause symptoms. It's often diagnosed by chance during tests for other breast conditions, such as a biopsy.

Please note that there is a type of breast cancer called invasive lobular breast cancer and this is different to LCIS.

Following a diagnosis of LCIS

Most women with LCIS will not get breast cancer. So you usually don't need to have any treatment.


Your doctor might suggest that you have regular monitoring because there is an increased risk of breast cancer. They might also call this close observation or careful observation.

You might have:

  • a breast examination every 6 to 12 months
  • a breast x-ray (mammogram) every year for about 5 years

If a cancer does start to develop, the monitoring should pick it up at a very early stage. Then you can have the treatment you need as early as possible.


You might have surgery rather than monitoring if you have a particular type of LCIS called pleomorphic LCIS.

You might have surgery to remove your breast (a mastectomy). Or you might have a wide local excision (a lumpectomy) to remove the LCIS and a surrounding area of normal tissue.

Hormone therapy

Your doctor might suggest that you take a type of hormone therapy. This lowers the chance of developing breast cancer in the future. Your doctor or breast care nurse will talk to you about the benefits and possible side effects of taking hormone therapy.

Trials and research

Research has focused on trying to find genetic changes that might increase the risk of developing LCIS. Trials have shown that some of the known genetic changes that increase the risk of breast cancer, also increase the risk of developing LCIS.

Researchers are also looking into using different types of hormone therapy to prevent invasive breast cancer after a diagnosis of LCIS.

The IBIS 2 prevention trial followed post menopausal women who took the hormone therapy, anastrozole (Arimidex), for 5 years. This included some women with LCIS. Results showed that hormone therapy did reduce the risk of breast cancer in these women.

Last reviewed: 
18 Oct 2017
  • Cancer Research UK statistics
    Accessed October 2017

  • Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind, randomised placebo-controlled trial 
    J Cuzick and others
    Lancet. 2014 Volume 383, Issue 9922

  • Is carcinoma in situ a precursor lesion of invasive breast cancer?
    T To and others
    International Journal of Cancer, 2014, volume 135, issue 7

  • LCA Breast Cancer Clinical Guidelines
    London Cancer Alliance West and South, October 2013

  • Recommendations for Women With Lobular Carcinoma In Situ (LCIS)
    BA Oppong and TA King
    Oncology, 25 October, 2011

  • The diagnosis and management of pre-invasive breast disease: Pathology of atypical lobular hyperplasia and lobular carcinoma in situ
    PT Simpson and others
    Breast Cancer Research, 2003, volume 5, issue 5

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