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Treatment of Ductal Carcinoma in Situ (DCIS)
Ductal carcinoma in situ (DCIS) means the cells lining 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. Even though DCIS cannot spread outside the breast, it is usually treated. This is because some DCIS cells can continue to change and develop into invasive breast cancer if they are left alone. Invasive breast cancer can spread.
If you have DCIS, you can usually choose between breast-conserving surgery (lumpectomy) and simple mastectomy. But if DCIS is throughout the breast, a mastectomy is sometimes a better option. Studies are underway to see if observation might be an option for some people instead of surgery.
Breast-conserving surgery (lumpectomy)
In breast-conserving surgery, the surgeon removes the tumor and a small amount of healthy breast tissue around it.
Lymph nodes: Lymph nodes usually do not need to be removed, but some might be removed after the first surgery if an area of invasive cancer is found. The chance that an area of DCIS contains invasive cancer increases with tumor size and higher tumor grade. If lymph nodes are removed, this is usually done as a sentinel lymph node biopsy.
Radiation therapy: Breast-conserving surgery is usually followed by radiation therapy. This is done to lower the risk of the cancer coming back in the same breast, either as more DCIS or as invasive cancer.
Breast-conserving surgery without radiation therapy is not a standard treatment, but it might be an option for people who are older or who have other significant health problems. It might also be an option if small areas of low-grade DCIS were removed with adequately clear (cancer-free) margins of tissue around the DCIS. The goal is a surgical margin of at least 2 mm. This is the current standard to minimize the risk of local recurrence.
Thousands of women have been studied over more than 20 years. These studies show that when breast-conserving surgery is done with radiation therapy in women with early-stage breast cancer, survival is the same as with mastectomy alone. The main advantage of breast-conserving surgery is that most of the breast is preserved.
Mastectomy
Simple mastectomy is removal of the entire breast.
It may be recommended when either:
- The area of DCIS is very large.
- DCIS is in multiple separate areas of the breast (multicentric disease).
- Breast-conserving surgery cannot achieve clear margins even after a second surgery.
The chance of finding invasive cancer is higher in these cases. Because of this, many surgeons will perform a sentinel lymph node biopsy (SLNB) at the time of the mastectomy.
If invasive cancer is found in the removed tissue and an SLNB was not done, it might not be possible to do one later. A full axillary lymph node dissection (ALND) may be required instead.
Most people who have a mastectomy for DCIS do not need radiation therapy. You may choose to have breast reconstruction right away or later.
Hormone therapy after breast surgery
If the DCIS is hormone receptor-positive, your cancer care team may recommend hormone therapy. Taking hormone therapy for 5 years after surgery can lower the risk of developing another DCIS or invasive cancer in either breast.
Options include:
- Tamoxifen
- Aromatase inhibitors, such as anastrozole or exemestane, for women who have gone through menopause
Talk with your cancer care team about the potential benefits and risks of hormone therapy to decide if it’s right for you.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg's Cancer: Principles and Practice of Oncology. 12th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2023.
Morrow M, Van Zee KJ, Solin LJ, et al. Society of Surgical Oncology–American Society for Radiation Oncology–American Society of Clinical Oncology Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Ductal Carcinoma In Situ. J Clin Oncol. 2016.
National Cancer Institute. Physician Data Query (PDQ). Breast Cancer Treatment – Health Professional Version. 2025. Accessed at https://www.cancer.gov/types/breast/hp/breast-treatment-pdq on May 4, 2026.
National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Breast Cancer. Version 2.2026. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on May 4, 2026.
Last Revised: July 9, 2026
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