Ductal carcinoma in situ (DCIS) is a breast condition where some cells that line the breast duct (the tube that carries milk to the nipple) do not appear normal. These cells stay in the breast duct and rarely spread into any other tissue. That is why DCIS is called a non-invasive breast condition. In some cases, DCIS may turn into a breast cancer, called an invasive breast cancer. This is where cancer cells spread to other breast tissue or organs. However, research has shown that the vast majority of DCIS might never become breast cancer.
DCIS is often misunderstood and it can be hard to define and explain. In addition, many specialists do not agree on how to best treat the condition. This may cause uncertainty, fear and worry for patients. There is also confusion about terms such as non-invasive or Stage Zero breast cancer for a condition that is not potentially life-threatening.
Most DCIS is found by mammograms in women who have no breast lumps or other symptoms. Before mammography, DCIS was rare and women who may have had the condition for many years were often unaware of it. Now, over 50,000 women are diagnosed with DCIS each year in the United States alone. This may be considered an unplanned consequence of mammography screening.
Ultrasound uses sound waves that bounce off tissue or organs in the body. The resulting echoes are turned into a picture to show breast mass. This can be used to take images of the breast. Women with dense breast tissue may want extra screening with ultrasound.
Magnetic Resonance Imaging (MRI)
MRIs use radio waves and a magnet to create detailed pictures of the body. This can highlight tissue that does not appear to be normal. MRI is not commonly used to screen for DCIS. However, it can be used if irregular spots are found on a mammogram. An MRI can provide information about how much DCIS exists. An MRI is also used to help decide what kind of surgery may be needed.
About 10% of women with DCIS are diagnosed because of symptoms such as nipple discharge, a breast lump, or skin changes. Patients with DCIS that is associated with symptoms are thought to be at higher risk of poor outcomes if not treated.
If you have suspicious findings on any of the examinations above, you will probably be referred for a biopsy. This is where a small amount of breast tissue is removed to check for disease. A doctor measures DCIS under a microscope to see if (and how) it is growing. There are three different types of grade of DCIS, based on the appearance of the cells. If cells are in between grades, they are called borderline.
- Low grade (lowest risk of aggressive growth)
- Medium grade (medium risk of aggressive growth)
- High grade (highest risk of aggressive growth)
There are two common types of breast biopsy. A core biopsy is where tissue is removed from a suspicious area of the breast with a needle. The core biopsy can either be directed with mammograms (stereotactic biopsy) or ultrasound (ultrasound-guided biopsy). This helps to identify any potential areas of concern. A further biopsy may be necessary if the core biopsy is not able to remove cells to give clear and definite results. If DCIS is diagnosed, a wider area of tissue may be removed. This is known as a surgical biopsy. It is also known as a wide local excision or a lumpectomy.
Reading this report and having confidence that it is correct are important. Future treatment options will be based upon it. A second pathology opinion may be requested. A copy of the report should be taken to any further consultations.
There is a wide range of DCIS with different cell size, grade, structure, and speed of growth. Knowing the type and grade of DCIS can help you and your doctor decide on the best treatment for you. A pathology report will state whether DCIS is low, medium, or high grade.
Estrogen and progesterone receptors are found in breast cancer cells that depend on estrogen and related hormones to grow. Women diagnosed with DCIS should have their estrogen and progesterone receptor status tested by a laboratory.
A small amount of healthy tissue around the DCIS may be removed. This is known as a clear margin or negative margin. If some DCIS is found at the edge of the tissue, it is known as a positive margin and is a signal that there could still be more DCIS in the breast. Another surgery is then necessary to obtain a clear margin. The importance of getting clear or clean margins is to try and reduce the chances of any DCIS returning in that part of the breast.
If cells that do not appear normal are found outside the breast duct, it is called an invasive cancer and is no longer considered DCIS. This is called upstaging (from DCIS to invasive cancer) and further treatments may be required.
Many researchers and doctors believe that there are some types of DCIS that grow so slowly that they would never cause symptoms during a patient’s life. For this type of DCIS, treatment may result in very little benefit. The DCIS that may have the lowest chance of becoming invasive cancer is called low-risk DCIS. Low-risk DCIS is generally thought to be DCIS that is grade I or grade II, sensitive to hormones, and does not cause symptoms. You should discuss with your doctor whether you might have low risk DCIS; if you do, you may be eligible for a trial that compares surgery to monitoring for low-risk DCIS.