Treatment of Ductal Carcinoma in Situ (DCIS)
Ductal carcinoma in situ (DCIS) means the cells that line the milk ducts of the breast have changed to look like cancer cells under a microscope, 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 still needs to be treated because it can sometimes go on to become invasive breast cancer.
In most cases, a woman with DCIS can choose between breast-conserving surgery (BCS) and simple mastectomy. But sometimes a mastectomy might be a better option.
Breast-conserving surgery (BCS)
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 always needed with BCS, but it may be done if the doctor thinks the area of DCIS might also contain invasive cancer. The risk of an area of DCIS containing invasive cancer goes up with tumor size and nuclear grade. 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 certain women who had small areas of low-grade DCIS that were removed with large enough cancer-free surgical margins.
Simple mastectomy (removal of the entire breast) may be needed if the area of DCIS is very large, if the breast has several areas of DCIS, 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). Many doctors will do a SLNB along with the mastectomy. This is because 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 the SLNB later, and so may have to do a full axillary lymph node dissection (ALND).
Women having a mastectomy for DCIS may choose to have breast reconstruction immediately or later.
Hormone therapy after surgery
If the DCIS is hormone receptor-positive (ER-positive or PR-positive), adjuvant treatment with tamoxifen (for any woman) or an aromatase inhibitor (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 pros and cons of hormone therapy with your doctors.
Morrow M, Burstein HJ, Harris JR. Chapter 79: Malignant Tumors of the Breast. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2015.
National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Breast Cancer. Version 2.2016. Accessed at www.nccn.org on June 1, 2016.
Wolff AC, Domchek SM, Davidson NE, Sacchini V, McCormick B. Chapter 91: Cancer of the Breast. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 5th ed. Philadelphia, Pa: Elsevier; 2014.
Last Medical Review: June 1, 2016 Last Revised: August 18, 2016
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