All eyes on DCIS

Dr Lucienne Van Schalkwyk educates us on the elusive pre-invasive form of breast cancer: ductal carcinoma in situ (DCIS).

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DCIS is an early, pre-invasive form of breast cancer, which is why we often refer to it as Stage 0 breast cancer.

Ductal carcinoma in situ (DCIS) is a very interesting disease. As it says in the name, it’s a form of breast cancer, however, it’s very different from invasive breast cancer in a few important ways. 

In DCIS, the cells lining the milk ducts of the breast become cancerous. The difference between DCIS and invasive breast cancer is the locations of the cancerous cells; in situ means that the abnormal cells are limited to the inside of the milk duct. 

Once the cancerous cells invade through the wall of the milk duct into the surrounding breast tissue, it becomes an invasive breast cancer, which can spread to the lymph nodes and other areas of the body through the blood vessels and lymphatic channels which are situated outside the wall of the milk duct. 

In essence, DCIS is an early, pre-invasive form of breast cancer; which is why we often refer to it as Stage 0 breast cancer. There is no way to predict when, or even if an area of DCIS will progress to an invasive breast cancer.

Like stars in the night sky

DCIS is most often without any symptoms, and as such is usually diagnosed incidentally on a screening mammogram. This is why it is so important to have regular mammograms even if you have no breast complaints. The earlier any abnormalities are identified, the better the chances of treating them successfully.

On mammogram, DCIS appears as small calcifications in the breast – tiny bright spots like stars in the night sky. Rarely, DCIS can cause a lump in the breast, blood-stained nipple discharge, or a scaly rash on the nipple. Just like with invasive breast cancer, we are not entirely sure why some people develop DCIS and others do not. Most likely a combination of genetic and lifestyle factors play a role.

A stereotactic biopsy

If your radiologist suspects that you may have DCIS, they will recommend a biopsy to confirm the diagnosis. It’s always best to have a needle biopsy, because it’s less invasive than a surgical biopsy. 

Because the calcifications of DCIS are very small, and most likely not visible on ultrasound, the biopsy is usually performed in the radiology suite under local anaesthetic, using the mammogram as guidance. This is called a stereotactic biopsy. 

During a stereotactic biopsy, you will either be sitting up or lying on your stomach, with your breast compressed in the mammogram machine. The radiologist uses the mammogram to identify the position of the abnormal area, and the machine then positions the biopsy needle in the correct area to take the biopsy. 

Not all radiology practices have the equipment required to perform a stereotactic biopsy. In this situation, your radiologist may arrange for you to be assisted at a practice that does. 

A biopsy can be a stressful experience, but your radiologist will check in with you frequently during the procedure to make sure that you are comfortable and will guide you through the process.

Identifying it as DCIS 

Once the pathologist has confirmed DCIS on the biopsy, they will assign a grade to it by looking at the appearance of the cells: Grade I, II or III (sometimes called low-, intermediate- or high grade). The more abnormal the cells, the higher the grade. 

Remember, the grade is different to the stage of the disease. Regardless of the grade assigned by the pathologist, the stage remains Stage 0. The pathologist will also check whether the DCIS is sensitive to hormones by checking for oestrogen receptors.

Treating DCIS

The primary treatment for DCIS is surgery. Your surgeon may request further scans, such as an MRI scan, to get a better idea of the size of the abnormal area before advising on what type of surgery is appropriate for you. 

The radiologist will also place a marker into the area of DCIS which will act as your surgeon’s GPS during the surgery, ensuring that the surgeon can find and remove the area. 

Small areas of DCIS can usually be treated successfully with a lumpectomy (removal of only the abnormal area of the breast), while large areas may require mastectomy (removal of the entire breast). 

If the DCIS involves the milk ducts directly behind your nipple, it may be necessary to remove the nipple to ensure that the malignant cells are removed with a clear margin. 

If you are having a lumpectomy, your surgeon will most likely not remove any lymph nodes from under your arm. However, if you are having a mastectomy, your surgeon will remove only the first lymph node downstream from the cancer (known as the sentinel lymph node). Should you wish to have breast reconstruction, your surgeon will arrange for the reconstructive surgeon to discuss the options with you.

Treatment after the surgery will be determined by the results of your pathology. Sometimes, when the entire area of DCIS is examined by the pathologist, small areas are identified where it has already infiltrated through the wall of the duct (micro-invasion). In this case, it’s treated as a very early stage invasive breast cancer. 

If the whole area is examined and found to truly be only DCIS, the treatment options include only monitoring the breast closely with follow-up mammograms, taking a hormone blocker tablet (known as endocrine therapy) for at least five years if your DCIS is hormone sensitive and/or a few sessions of radiation. The hormone blocker and radiation both act to decrease the risk of the DCIS coming back in future. 

Your treatment plan may be very different from someone else’s; it’s individually tailored to your cancer and your personal health history. It’s vitally important that your treatment plan is discussed at a multi-disciplinary meeting that includes specialists from different disciplines (surgeons, pathologists, oncologists, radiologists) to ensure that your treatment is, as Goldilocks would say: Not too little. Not too much. Just right!

Dr Lucienne van Schalkwyk is a general surgeon with a special interest in breast surgery. Her practice manages the entire spectrum of benign and malignant breast disease, and her specific interests include breast-conserving surgery and oncoplastic surgical techniques.

MEET THE EXPERT – Dr Lucienne van Schalkwyk

Dr Lucienne van Schalkwyk is a general surgeon with a special interest in breast surgery. Her practice manages the entire spectrum of benign and malignant breast disease, and her specific interests include breast-conserving surgery and oncoplastic surgical techniques.

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