Surgeon simply explains breast ductal carcinoma in-situ (DCIS).

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06/19/23

Breast surgeon describes DCIS (Ductal Carcinoma In-Situ) of the breast. DCIS is not true breast cancer, I like to explain it to women as “pre-cancerous”. DCIS stands for ductal carcinoma in situ. The breast is designed to deliver milk to the nipple during pregnancy. The milk is produced in a part of the breast called the lobule and travels to nipple through tubes called ducts. There are thousands of these duct units throughout the breast. About 80% of breast cancers come from the duct cells whereas only 20% come from the lobule cells. As the duct cells become cancerous they are stuck inside of the duct tube and when they have not invaded through the wall of the duct they are called in-situ. Only after the cancerous cells have invaded through the wall of the duct into the surrounding breast tissue are they considered invasive breast cancer. Because there are no lymphatic channels or blood vessels inside of the ducts, DCIS cells cannot travel from the breast to lymph nodes and cannot spread – they are stuck in the duct which is why I tell women these are pre-cancerous because, by definition, the bad cells cannot get out of the breast tissue to cause harm. As the DCIS cells form in the ducts they grow abnormally and many cells die. As the abnormal cells die they leave calcium deposits in the ducts which shows up on the mammograms as spots of calcium. Radiology doctors are especially concerned if the calcium deposits on the mammogram are new, changing, or in the shape of branching ducts. Very occasionally a woman may have a lump they feel or bloody fluid coming out of the nipple that can be a sign of DCIS cells in the breast but the vast majority are found on screening mammograms. The abnormal area is biopsied using a mammogram machine to guide it since the calcium is usually easiest to see on mammogram x-rays and MRI biopsies are harder to do. Once the area is biopsied, we leave a small ****anium marker in the exact area that was biopsied – this is so we can find the same area again in the future if the biopsy turns out to be cancerous. Once a biopsy shows DCIS, the first treatment is surgery. There are two types of surgery for DCIS in the breast – either a lumpectomy which is removing a portion of the breast, or a mastectomy which is removing the entire breast. For a lumpectomy – we usually need something as surgeons to help us know we are removing the correct piece of the breast tissue. DCIS is usually NOT something you can feel and you can’t see it with the naked eye. The most common way of finding the area is for a radiologist to place a wire through the skin with a J shaped hook at the end that prevents it from pulling out. The tip of the wire at the J hook will be placed as close as possible to the clip that was left from the needle biopsy that found the DCIS. When the surgery is performed, the surgeon finds the wire usually just below the skin and follows it to find the area of the breast that should be removed. One thing that is important to know when we offer a lumpectomy for DCIS is that radiation to the remaining breast is usually recommended. If we don’t give radiation after removing a piece of DCIS we usually say the risk of future DCIS or even invasive breast cancer is nearly 50%. But if you give radiation the chance of having DCIS or cancer regrow is more like 10%. Since the DCIS cells are “stuck” in the duct and cannot travel to lymph nodes we don’t do any armpit lymph node removal when we do a lumpectomy for DCIS.
The other surgical option is mastectomy. Mastectomy removes all of the breast tissue. Also, even though I said DCIS can’t get into the lymph nodes – sometimes when we remove the entire DCIS area we find a part that has invasive breast cancer that the needle biopsy missed. So if we are doing a mastectomy, that is our one chance to check the lymph nodes for cancer via the Sentinel lymph node biopsy technique – also explained in a different video of mine – and it is a good idea to do the lymph node check during the mastectomy for DCIS on the small chance you find invasive cancer in the breast after you take it out. Now because there is no breast tissue left after a mastectomy, there is no reason to give radiation. So a mastectomy does prevent the need for radiation to DCIS of the breast. As far as breast reconstruction – that is a topic for a different talk but suffice it to say that reconstruction should definitely be an option after a mastectomy for DCIS. So after a lumpectomy for DCIS, after one month of healing radiation is given to the remaining breast. After surgery and radiation, you should see medical oncology to discuss medicine to block the effects of estrogen on the breast tissue. This can help decrease the chance of DCIS re-growing or new areas of breast cancer.