Lobular carcinoma in situ (LCIS)

Lobular carcinoma in situ (LCIS) is not a cancer. But it can increase the risk of developing cancer.

What is lobular carcinoma in situ (LCIS)?

The breast contains lobules. These are where milk is made. Sometimes there are abnormal changes in the cells that line the lobules. When this happens, it is called lobular carcinoma in situ (LCIS). LCIS is also called lobular neoplasia.

LCIS is not cancer. But it can increase the risk of breast cancer later in life. Most women with LCIS do not develop breast cancer. LCIS is very rare in men.

LCIS is more common if you have not been through the menopause. It is more common between 40 and 50 years old.

If LCIS is only diagnosed in 1 breast, the risk of developing cancer in both breasts increases. Sometimes LCIS is found in both breasts.

Side view of the breast

The diagram shows a cross-section of the breast, including the lobules, milk ducts, fatty tissue, muscle and ribs.
Image: The diagram shows a cross-section of the breast from the side. It shows a number of lobules throughout the breast and these are all joined to the nipple by small tubes called milk ducts. Surrounding the lobules in the breast is fatty tissue. Behind the breast is a layer of muscle and behind this are some of the ribs.

How is LCIS diagnosed?

LCIS usually has no symptoms, and it does not show on a mammogram. It is usually found by chance. This could be after a biopsy or when a breast lump is removed for another reason – for example, if breast calcifications are found on a mammogram.

If LCIS is diagnosed after a needle or vacuum-assisted biopsy, you may need more tissue removed. This means having a small operation called an excision biopsy. You usually have this to make sure there are no cancer cells in the area.

The surgeon removes the tissue under a general or local anaesthetic. They may use an ultrasound or mammogram to help guide them to the area. The removed tissue is then sent to a laboratory, where it is checked under a microscope.

If you have an excision biopsy, you can usually go home on the same day.

Managing LCIS

If you have LCIS, you will not need any treatment. LCIS usually does not cause any problems. Most people with LCIS do not develop breast cancer, so they never need treatment. You will be offered regular monitoring. This is to make sure that if a cancer develops, it is found early.

If you develop breast cancer, you can start treatment straight away. Treatment for early breast cancer is usually very successful. Your specialist doctor and nurse will explain what happens after treatment (your follow-up).

There is a rare type of LCIS called pleomorphic LCIS. It is usually treated in a similar way to ductal carcinoma in situ (DCIS). If you are diagnosed with this type of LCIS, your doctor or nurse will explain more about it.

Monitoring or screening

Doctors usually recommend having mammograms every 1 to 2 years. Some people may also be offered MRI scans. This is called monitoring.

Even if you are having monitoring, it is still important to know how your breasts look and feel at different times of the month. This means you will know what is normal for you.

Changes to look for include:

  • a lump in the breast
  • a change in the size or shape of the breast
  • the skin of your breast feeling thicker
  • a nipple that is turned in (inverted)
  • an eczema-like rash on the nipple or breast
  • leaking (discharge) from the nipple
  • swelling or a lump in the armpit
  • discomfort or pain in the breast that does not go away.

If you notice any changes, tell your doctor or nurse as soon as possible. The changes could be for many reasons other than cancer.

Booklets and resources

Lowering the risk of breast cancer

Hormonal therapy is usually given to people who have had treatment for breast cancer. It aims to reduce the risk of cancer coming back. If you have LCIS, you may be offered hormonal therapy drugs to reduce the risk of breast cancer developing.

It is not clear how much reducing the risk of cancer outweighs the side effects of hormonal therapy drugs. Tamoxifen is a hormonal therapy drug that is sometimes used in this situation. If you are struggling with its side effects, it may be possible to have a reduced dose that causes fewer side effects.

Your doctor or nurse will talk to you about taking hormonal therapy drugs if these are an option for you. They will discuss the benefits and risks with you.

If you are diagnosed with LCIS, your doctor or nurse will ask about your general health and your family history. This is to find out whether there is a pattern of breast cancer in your family.

If your doctor or nurse thinks you have a strong family history of breast cancer, they will refer you to a genetics clinic to see a specialist. At the clinic, you have a risk assessment and genetic counselling.

Some women who are assessed as having a high risk of breast cancer, may think about having surgery to remove both breasts removed. This is to reduce the risk of breast cancer developing. It is called risk-reducing breast surgery. It is important to talk to your doctor about the potential risks and benefits before making a decision.

Talk to your doctor or specialist nurse if you are worried about your family history or risk of developing breast cancer.

Your feelings about LCIS

It is natural to feel worried if you know you have an increased risk of breast cancer. But LCIS is not cancer, and most people with LCIS do not develop breast cancer.

It can be reassuring to know that you will have regular checks and support from your doctor and nurse. Talk to them about any concerns you have.

Macmillan is also here to support you. If you would like to talk, you can:

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Rebecca Roylance, Consultant Medical Oncologist and Professor Mike Dixon, Professor of Surgery and Consultant Breast Surgeon.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
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  • use illustrations to explain text
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We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 October 2023
Next review: 01 October 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.