DCIS – DUCTAL CARCINOMA IN SITU

This page contains information about cases in which a biopsy has been done, whether for a lump or other abnormality on exam, or for an abnormal mammogram, and the biopsy shows ductal carcinoma in situ (DCIS).  This is different from “ductal carcinoma” or “invasive ductal carcinoma.

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I had a breast biopsy that showed ductal carcinoma in situ (DCIS). What should be done now?

Although no one ever wants to be told that they have cancer, the finding of ductal carcinoma in situ (DCIS) is one of those situations where we truly have found a cancer at a stage where it can be nipped in the bud.  (In fact, some would even argue that it is not really a cancer “yet”, if it has not actually invaded into the surrounding tissue.) The “in situ” phrase means that we can tell for sure that these cells have the POTENTIAL to do their cancer thing (which means, to invade into surrounding tissue and eventually spread elsewhere), but that they have not yet invaded even the tissue right around the DCIS cells. You can think of these cells as “cancer seeds”, which haven’t yet sprouted, but have all the capability of doing so if left in place.

When DCIS is seen on a biopsy, you will usually need to have more tissue removed from your breast (usually the additional tissue removed is about the size of an ice cream scoop). This is almost always done as on open surgical excision in the operating room, either with sedation or general anesthesia, though sometimes under local anesthesia. This surgical excision is the most important treatment, and it is necessary to remove enough tissue so that none of the DCIS is seen along any of the margins of the removed tissue.

This is not always as simple as it might seem, because the DCIS can only be seen under the microscope, and the tissue is not usually examined under the microscope until after preserving the removed tissue in formalin overnight. This method gives more reliable information than trying to examine the tissue immediately (called a frozen section). This means that there are some women in whom the margins will show some more DCIS, and this will require another trip to the operating room to remove more tissue. This return to the operating room is necessary more often than you might think, as often as 50% of the time at some centers, whether here in Atlanta, or at an academic center. At DeKalb Surgical, this is only necessary about 10% of the time. I wish it would never happen, but sometimes even the non-invasive cancer cells can extend along the breast ducts in various directions. Obtaining clear margins is a matter of experience, compulsion with orientation of the tissue for the pathologist, and to some extent, how much additional breast tissue is removed.

In some cases, when the surgical excision is done, there may be some actual invasion seen in an adjacent area, that was not seen on the initial biopsy. In such cases, the situation changes a bit. In most cases of invasive cancer, even if only a tiny area, it is usually recommended to also surgically check some of the lymph nodes under your arm, to be sure there are no cancer cells seen there. You will find more information about this on the invasive cancer page.

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Although surgical excision for clear margins is the most important treatment for DCIS, radiation therapy AND 5 years of anti-hormonal therapy (with tamoxifen) is fairly standard additional treatment, with the intention of minimizing the possibility that you might ever develop another cancer in your breast. There is no need for chemotherapy in these very early stage cases. Your surgeon should discuss these issues with you in more detail. Probably the most important thing to remember if you have DCIS is that essentially all women are cured of their cancer when it is found at this stage.

You may wonder why radiation therapy and hormone-blocking treatment are recommended if all the DCIS is surgically removed. That’s a good question, and the answer comes from what we have learned over the past several decades of treating such patients. Studies have compared treatment with lumpectomy only versus lumpectomy plus giving radiation therapy, and also with or without giving hormone blocking treatment (tamoxifen). These studies showed that a higher percentage of patients who only had lumpectomy had cancer come back again over the following 5-10 years. And when the cancer comes back, sometimes it is invasive instead of non-invasive. After lumpectomy only, the recurrence rate is about 35%. If radiation therapy and tamoxifen are added, the recurrence risk is under 5%.

I like to think of the radiation therapy in this case as analogous to the weed preventive that you might apply to your yard in the spring. You might have had one sprig of crabgrass that you pulled out completely. You don’t see any other crabgrass in your yard, but you figure that it could pop up at a later date. The weed preventive will do just that—help prevent you from having more crabgrass in the future. In the same way, just removing the seeds of breast cancer (DCIS) might not be enough to keep some seeds sprouting and taking root elsewhere in your breast in the future. Radiation therapy decreases that risk considerably I most cases.

It is important to understand that the treatment of breast cancer, and DCIS, is evolving.  Currently there is interest in trying to identify subsets of women for whom we feel the risk of invasive disease in the future is so low that we could avoid the usual radiation therapy and anti-hormonal therapy.  Such treatment decisions can be individualized, and in your particular case, your priorities should certainly be considered in deciding on what treatment you ultimately received.  Your priorities are given the uppermost consideration at DeKalb Surgical in formulating an individualized treatment plan.

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