Lobular carcinoma in situ (LCIS)

Lobular carcinoma in situ (LCIS) means that cells inside some of the breast lobules have started to become abnormal. LCIS It is not a cancer.

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.

LCIS is not a cancer, but having it means that you have a small 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 735 people are diagnosed with LCIS each year in the United Kingdom.

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.


Most women with LCIS will not get breast cancer. So you may not 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 breast conserving surgery (a wide local excision) 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.

  • Early Breast Cancer: ESMO Clinical Practice Guidelines
    F Cardoso and others 
    Annals of oncology, 2019. Volume 30, Pages 1194-1220.

  • LCA Breast Cancer Clinical Guidelines
    London Cancer Alliance, West and South
    October 2013 (updated March 2016)

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

  • Cancer Research UK statistics
    Accessed June 2020

  • Lobular Carcinoma In Situ
    Y Wen Hannah and E Brogi
    Surgical Pathology Clinics, 2018. Volume 11, Issue 1, Pages 123–145.

  • AJCC Cancer Staging Manual (8th edition)
    American Joint Committee on Cancer
    Springer, 2016

Last reviewed: 
19 Jun 2020
Next review due: 
19 Jun 2023

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