PATH 1: Early Stage Breast Cancer

PATH 2: Neoadjuvant Therapy

PATH 3: Pregnancy During Breast Cancer


PATH 5: Metastatic Stage 4

Ductal Carcinoma In-Situ (DCIS)

Ductal Carcinoma In-Situ (DCIS), or Stage 0, is the earliest stage of breast cancer. This form of breast cancer is non-invasive, meaning the cancer cells have not left the breast duct and have not spread into the rest of the breast. This condition is highly treatable and often needs less treatment steps compared to other breast cancers. For DCIS, you will likely only need surgery to remove the cells and radiation to kill any remaining cancers. 

On this page, you will be introduced to DCIS and its treatment options. You will also find useful websites with more information. 


What is DCIS? 

Ductal carcinoma in-situ (DCIS) is the presence of atypical cells within the ducts of the breast. In-situ means that the cells are “trapped” within the walls of the ducts. These cells are not able to invade outside of the duct and spread into the rest of the breast tissue, lymph nodes or to other parts of your body; therefore, DCIS is not considered an invasive breast cancer and is labeled Stage 0. Overall, patients with DCIS do very well, as it is a very treatable condition. 
Because DCIS is trapped within the milk ducts of the breast, it usually has no symptoms and is often discovered on a mammogram. Less commonly, it may be felt as a lump or be associated with nipple discharge. It is common to be diagnosed on a needle biopsy of the breast based on your mammogram. 

What is the difference between DCIS and invasive duct cancer? 

If the cells invade through the duct wall, it is no longer trapped inside the duct and is now called an “invasive” cancer because it has gone through the wall into the breast tissue. 

Sometimes DCIS is found with invasive cancer right away on the needle biopsy, and when that happens, the invasive cancer (not the DCIS) drives the treatments and behaviour

Sometimes when the diagnosis of DCIS is made with a needle biopsy, we can find signs that the cells have invaded outside the duct. When this happens in a very small area (less than one millimetre), then it is called microinvasion or microinvasive DCIS—meaning a very small area. The behaviour of microinvasive DCIS is similar to pure DCIS and is a very treatable condition. When the area of invasion is larger than that, the diagnosis changes to invasive cancer.
The following information is most relevant for women with a diagnosis of just DCIS, with no current signs of invasive cancer. 


The main focus of treatment for DCIS is to prevent it from progressing into an invasive cancer or returning as more DCIS in the future. Not all DCIS will progress into invasive cancer, but we cannot reliably predict which patients with DCIS are more likely to progress than others. As a general rule, most very young women with DCIS have features that are considered more likely to progress, such as higher grade (see diagnosis) or large size. Therefore, young women with DCIS are often recommended to have treatment to decrease the chances it will progress or return.

Because DCIS has no ability to spread to lymph nodes or other parts of the body, the treatment is focused on the breast itself. The main treatment for DCIS is to remove it through surgery

The most common surgical management is to just remove the area where the cells are. This is called breast-conserving surgery or lumpectomy or partial mastectomy.

Sometimes mastectomy may be required or desired based on the extent of your disease. Reconstruction of the breast is commonly part of treatment covered by your provincial health care and is sometimes performed at the same time as the mastectomy or at a later date.

After breast conserving surgery, radiation is given to the whole breast to reduce the risk of recurrence of DCIS or of invasive cancer.

To further reduce the risk of recurrence after breast conserving surgery and radiation, hormonal therapy may be recommended if your DCIS is estrogen positive. 

Chemotherapy is not required for DCIS because DCIS is not something that is able to travel in the body.

Lymph nodes

Since DCIS does not have the capacity to spread to lymph nodes or to the remainder of the body, sampling of lymph nodes (sentinel lymph node biopsy or SLNB) is not required at the time of your surgery if you are having breast-conserving surgery. Staging is also not required. 

Occasionally, the final pathology from surgery (after a needle biopsy diagnosis of DCIS) finds areas of invasive cancer. If this happens, you will need a SLNB and your treatment will be adjusted for invasive cancer. 
A SLNB requires some remaining breast tissue in order to be performed. Due to this fact, if you have a mastectomy for DCIS, a SLNB will also be performed in case any areas of invasive cancer are identified on the final pathology. 


If you are working, there is no need to stop working if you feel up to it, but this is the time to take care of yourself

At this point, you may be preparing to tell your loved ones about your diagnosis if you haven't already. This is a personal decision, but confiding in someone may provide you with some emotional support. 

You may also decide that participating in clinical trials is the right choice for you. Again, this is a personal decision, but many options are available.  


At this stage you will start to process the information and begin the process of coping with the diagnosis emotionally and physically. 
You may feel scared, angry, sad and out of control. Many people begin to experience anxiety as well. These feelings are common, normal and expected. Your personal and medical support team can help you work through these feelings, and you may find that reading other women's stories is beneficial. Our resource directory may also help guide you through your feelings. 
Many women feel that the cancer is growing every second, spreading rapidly, and that every new pain or feeling in the body is a sign of the cancer. This is a very normal reaction to the news, and while it feels like treatment can’t happen fast enough, the important thing to remember that the majority of breast cancers do not spread like that and that the very first cell was probably there months or even a year or so ago. 


Depending on who organized your biopsy, you will be referred to a specialist who will meet with you and discuss a treatment plan. This may be a surgeon or an oncologist or both. You will also see a nurse and radiologist throughout the diagnosis stage. Depending on your treatment plan, you may see a medical and/or radiation oncologist, psychologist/psychiatrist and genetic counselor as well.

Ideally, you should prepare for your appointment and bring along someone who knows you well and can be a second set of ears during the consultation. You might consider recording your appointments on your smart phone as well. 

Be sure to ask plenty of questions to help yourself gain the best undertanding of your situation.