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Ductal carcinoma in situ (DCIS) means the cells that line the milk ducts of the breast have become cancer, but they have not spread into surrounding breast tissue.
DCIS is considered non-invasive or pre-invasive breast cancer. DCIS can’t spread outside the breast, but it is often treated because if left alone, some DCIS cells can continue to undergo abnormal changes that cause it to become invasive breast cancer (which can spread).
In most cases, a woman with DCIS can choose between breast-conserving surgery (BCS) and simple mastectomy. But sometimes, if DCIS is throughout the breast, a mastectomy might be a better option. There are clinical studies being done to see if observation instead of surgery might be an option for some women.
In breast-conserving surgery (BCS), the surgeon removes the tumor and a small amount of normal breast tissue around it. Lymph node removal is not usually needed with BCS. It might be done after the first surgery if an area of invasive cancer is found. The chances an area of DCIS contains invasive cancer goes up with tumor size and how fast the cancer is growing. If lymph nodes are removed, this is usually done as a sentinel lymph node biopsy (SLNB).
If BCS is done, it is usually followed by radiation therapy. This lowers the chance of the cancer coming back in the same breast (either as more DCIS or as an invasive cancer). BCS without radiation therapy is not a standard treatment, but it might be an option for older women, women with other significant health problems, or women who had small areas of low-grade DCIS that were removed with large enough cancer-free surgical margins.
Many women with early-stage breast cancer, like DCIS, can choose between breast-conserving surgery (BCS) and mastectomy. The main advantage of BCS is that a woman keeps most of her breast. Some women might worry that having less extensive surgery might raise their risk of the cancer coming back. But studies following thousands of women for more than 20 years show that when BCS is done with radiation in women with early-stage cancer , survival is the same as having a mastectomy.
Simple mastectomy (removal of the entire breast) may be needed if the area of DCIS is very large, if the breast has several separate areas of DCIS in different quadrants (multicentric), or if BCS cannot remove the DCIS completely (that is, the BCS specimen and re-excision specimens still have cancer cells in or near the surgical margins). If a mastectomy is needed for any of the reasons stated above, many doctors will do a SLNB along with the mastectomy because there is a higher chance that invasive cancer might be found. If an area of invasive cancer is found in the tissue removed during a mastectomy, the doctor won’t be able to go back and do SLNB later, and as a result may have to do a full axillary lymph node dissection (ALND) instead.
Women having a mastectomy for DCIS typically don’t need radiation therapy and may choose to have breast reconstruction right away or later.
If the DCIS is hormone receptor-positive (estrogen or progesterone), treatment with tamoxifen (for any woman) or an aromatase inhibitor, such as exemestane or anastrozole, (for women past menopause) for 5 years after surgery can lower the risk of another DCIS or invasive cancer developing in either breast. If you have hormone receptor-positive DCIS, discuss the reasons for and against hormone therapy with your doctor.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Collins LC, Laronga C, and Wong JS. Ductal carcinoma in situ: Treatment and prognosis. In Vora SR, ed. UpToDate. Waltham, Mass.: UpToDate, 2021. https://www.uptodate.com. Last updated July 13, 2021. Accessed August 17, 2021.
Henry NL, Shah PD, Haider I, Freer PE, Jagsi R, Sabel MS. Chapter 88: Cancer of the Breast. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.
Jagsi R, King TA, Lehman C, Morrow M, Harris JR, Burstein HJ. Chapter 79: Malignant Tumors of the Breast. In: DeVita VT, Lawrence TS, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.
National Cancer Institute. Physician Data Query (PDQ). Breast Cancer Treatment – Health Professional Version. 2021. Accessed at https://www.cancer.gov/types/breast/hp/breast-treatment-pdq on August 17, 2021.
National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Breast Cancer. Version 6.2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on August 17, 2021.
Last Revised: October 27, 2021
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