What is ductal carcinoma in situ (DCIS)?

Ductal carcinoma in situ (DCIS) is the earliest possible form of breast cancer. It needs to be treated but is not life-threatening.

Breast cancer usually starts in the cells that line the lobules and the milk ducts that carry milk from the lobule out through the nipple. The place where DCIS starts is the terminal duct lobular unit. In this information, we use the simpler terms lobules and ducts.

In DCIS, the cancer cells are completely contained in the ducts and lobules. The cells have not broken through the walls of the lobules or ducts or grown into surrounding breast tissue. This is because the cells are not yet able to invade other tissues.

Side view of the breast

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DCIS and invasive breast cancer

If DCIS is not treated, over time it may spread into (invade) the breast tissue surrounding the ducts. It then becomes an invasive breast cancer.

Not every untreated DCIS will develop into an invasive breast cancer. But breast specialists usually advise treating DCIS. This is because it is not possible to tell for certain which individual cases of DCIS will become an invasive cancer.

Having DCIS means you have a slightly higher risk of getting cancer elsewhere in the same breast or in your other breast.

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Symptoms of DCIS

Most women with DCIS have no symptoms and are diagnosed through breast screening as part of the NHS breast screening programme.

A small number of women go to their GP with breast symptoms and are referred for a mammogram. DCIS is then diagnosed. Their symptoms may include:

  • a lump in the breast
  • discharge or bleeding from the nipple
  • a rash (like eczema) or itching on or around the nipple.

Always see your GP if you have any of these symptoms or any other breast symptoms.

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Causes of DCIS

Doctors do not know the exact causes of DCIS. But there are risk factors that can increase your chance of developing it.

The risk factors for DCIS and invasive breast cancer are similar. DCIS is likely to be caused by a combination of different risk factors, rather than just one.

Diagnosis of DCIS

DCIS is usually found through changes seen on a mammogram (a low-dose x-ray of the breast). When breast cancer is found by screening in the UK, 1 in 5 cases (20%) are DCIS.

A small number of women go to their GP with symptoms and are referred for a mammogram.

DCIS usually shows on a mammogram as an area of tiny specks of calcium, known as micro-calcifications. They are common as women get older and are usually harmless. But rarely, a group of micro-calcifications in one area (cluster) be a sign of DCIS or early breast cancer.

If micro-calcifications are found, you will usually have a magnified mammogram, to examine the area more closely.

Further tests

If your mammogram shows signs of DCIS, you will be referred to a breast assessment clinic for further tests.

You will see a specialist breast doctor or a nurse practitioner. You may also see a breast care nurse. They usually ask you if:

  • you have had any other breast problems
  • anyone in your family has had breast cancer.

The doctor or nurse will examine your breast and the lymph nodes in your armpits and around your neck.

After your examination, your doctor or nurse will explain you what tests you need:

  • Mammograms

    You may have more mammograms that focus on the area of DCIS. These can be taken from different angles or use magnification.

  • Breast ultrasound

    An ultrasound uses sound-waves to build up a picture of the breast tissue. You will also have an ultrasound on the lymph nodes in the armpit.

  • Breast biopsy

    There are different ways you may have a biopsy. The doctor removes a small piece of tissue or a sample of cells from the lump or abnormal area. The sample is then checked for cancer cells.

You may have many of these tests on the same day, as well as getting the results. But you might have to wait up to 2 weeks for some results. The staff at the clinic will let you know how and when you will get your results. We have more information on waiting for test results.

Staging, grading and receptors for DCIS

To plan your treatment, your breast specialist needs to know the following:

  • The stage of the cancer
    Staging describes the cancer’s size and how far it has spread. DCIS can be any size, but will always be described as stage 0. This is the earliest stage with no invasive breast cancer.
  • The grade of the cancer
    The grade of a cancer describes how the cells look compared with normal cells under the microscope. This gives doctors information about how quickly the cancer might grow or spread.
  • Whether the cancer has certain hormone receptors
    Tissue that was removed during biopsy is tested for receptors (proteins). These receptors allow hormones such as oestrogen, to attach to DCIS cells. When hormones attach to DCIS cells they can help them to grow. Your doctor may suggest taking drugs called hormone therapies that reduce levels of oestrogen in the body.

Treatment for DCIS

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

After the MDT your cancer doctor or specialist nurse will talk to you about the treatment options. They will explain the different treatments and their side effects. You can decide together on the best treatment plan for you.

The main treatment is surgery to remove the DCIS. The aim of treatment is to remove the cancer and reduce the risk of it developing into invasive breast cancer.

Some women may have other treatments such as radiotherapy or hormone therapy.

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.


The operation you have to remove DCIS depends on the size and postion of the DCIS, and your own preferences.

There are different types of surgery you may have:

  • Most women have breast-conserving surgery, this aims to to keep as much of the breast and it's shape as possible.
  • Sometimes, you are advised to have the whole breast removed (mastectomy).
  • If you have a mastectomy, you will also have a sentinel lymph node biopsy (SNLB). This is a way of checking lymph nodes in the armpit for cancer cells.
  • Some women choose to have surgery to make a new breast shape (breast reconstruction). Breast reconstruction can be done at the same time as the operation to remove cancer. Or you can choose to have this done later.

Some different types of breast surgery work equally well in treating DCIS. This means your surgeon and specialist nurse may give you a choice of treatment. They will explain what is involved and the possible side effects to help you make your decision.

We have more information on what to expect from your operation. You may need support when dealing with changes to your body after surgery.

Other treatments

You may also have other treatments:

  • Radiotherapy

    After breast-conserving surgery, your cancer doctor will usually advise you to have radiotherapy to reduce the risk of DCIS coming back.

  • Hormonal therapy

    If you have DCIS that is oestrogen-receptor (ER) positive, your doctor may talk to you about having hormonal therapy. Some ER positive women may have hormone therapy before their operation. This is to shrink the DCIS so that you can have breast conserving surgery instead of mastectomy.

After DCIS treatment

Follow-up after treatment

As part of your follow-up treatment, you will have yearly mammograms.

You may have routine appointments with your doctor or breast care nurse, or they may give you information on what to look out for.

Your treated breast will look and feel different. If you notice anything unusual between appointments, contact your cancer specialist or breast care nurse straight away.

After treatment, the risk of DCIS coming back or of getting an invasive breast cancer is low. If this happens, treatment is usually very successful.

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation. 

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

Sex life and fertility

Breast cancer treatments can have a direct effect on your sex life.

For example, surgery may affect how you think and feel about your body (body image). It can take time to adjust to changes to your body. If you have a partner, it can help to talk openly with them about your feelings.

Some treatments for DCIS may cause menopausal symptoms. Doctors do not recommend hormone replacement therapy (HRT). This is because it contains oestrogen, which could encourage breast cancer cells to grow.

Your cancer doctor or breast care nurse will also advise you not to use contraception that contains hormones.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.

Making small changes to the way you live such as eating well and keeping active can improve your health and well-being and help your body recover.

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About our information

  • References

    Below is a sample of the sources used in our ductal carcinoma in situ (DCIS) information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    European Society for Medical Oncology. Primary breast cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of oncology 26 (supplement 5): v8–v30. 2015. 

    Morrow M, et al. Chapter 79: malignant tumors of the breast. DeVita, Hellman and Rosenberg’s cancer: principals and practice of oncology (10th edition). Lippincott Williams and Wilkins. 2014.

    National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management. July 2018.

    Scottish Intercollegiate Guidelines Network. SIGN 134. Treatment of primary breast cancer: a national clinical guideline. September 2013.


  • 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 Senior Medical Editor, Professor J Michael Dixon, Professor of Surgery and Consultant 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.

Reviewed: 31 October 2018
Reviewed: 31/10/2018
Next review: 01 April 2021
Next review: 01/04/2021

This content is currently being reviewed. New information will be coming soon.