Carcinoma in Situ Breast Cancer
Medically reviewed by Dr. C.H. Weaver M.D. 10/2018
There are two types of breast carcinoma in situ: ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). DCIS is a very early stage of breast cancer in which the abnormal cells are confined to the lining of breast ducts. If not treated, some cases of DCIS cases will progress to invasive cancer. LCIS, in contrast, is not believed to be a direct cancer precursor, but does indicate that a woman is at increased risk of developing breast cancer. The role of early treatment is less clear for patients with LCIS.
For more information, go to Lobular Carcinoma In Situ.
Ductal Carcinoma in Situ
Ductal carcinoma in situ (DCIS) is the earliest possible clinical diagnosis of breast cancer and is frequently diagnosed with screening mammography that has detected small areas of calcification in the breast. Patients rarely suspect that they have breast cancer with this stage cancer. Diagnoses of DCIS has increased greatly once mammography became widespread, and DCIS now accounts for up to one-quarter of all breast cancer diagnoses in the United States.
The following is a general overview of the treatment of DCIS. The information on this Web site is intended to help educate you about your treatment options and to facilitate a mutual or shared decision-making process with your treating cancer physician.
The Role of Surgery For DCIS
In the past, surgical removal of the affected breast, called mastectomy, was recommended for the treatment of DCIS. This treatment has resulted in cure rates of 98 to 99%. Rare cancer recurrences occur in the axilla, the opposite breast, or at distant sites. Because of this success, doctors began using breast-conserving surgery to treat DCIS successfully, without removal of the entire breast. This type of surgery may involve a partial mastectomy (removal of the cancer, some of the healthy breast tissue, and sometimes the area lymph nodes), or a lumpectomy (removal of the cancer and the tissue around the cancer).
Axillary lymph node dissection is not routinely performed for DCIS because it’s uncommon for DCIS to involve the lymph nodes. In certain situations, however, sentinel lymph node biopsy may be considered.
Total Mastectomy: Total mastectomy involves complete removal of the breast and is associated with a cure rate of nearly 98-99%. Women treated with total mastectomy require no additional treatment to the affected breast.
Breast-Conserving Surgery: Although no randomized trials have been performed, breast-conserving surgery has been used successfully to treat DCIS in the last 30 years. A current goal of treatment for women with DCIS is breast conservation with an optimal cosmetic effect and a minimum risk of subsequent invasive or in situ cancer recurrence.
For some patients with small cancers and wide surgical margins, surgery alone is probably curative, with an extremely low rate of recurrence. However, in general, most patients undergoing breast-conserving surgery will probably be advised to receive radiation therapy with or without hormonal treatment for maximum prevention of recurrences.
Role of Radiation Therapy For DCIS
Patients treated with mastectomy generally do not need additional treatment with radiation therapy. When DCIS is treated with breast-conserving surgery, additional treatment with radiation therapy has been shown to reduce the risk of cancer recurrence. The benefits provided by radiation therapy, however, may vary depending on the underlying biology of the DCIS.
To learn more about Radiation Therapy
Role of Hormonal Therapy For DCIS
Among women who have estrogen receptor-positive DCIS of the breast, adjuvant (post-surgery) treatment with hormonal therapy may reduce the risk of subsequent breast cancer.
Estrogen is a female hormone produced mainly by the ovaries. Many organs in the body are composed of cells that respond to or are regulated by exposure to estrogen. Cells in the breast, uterus and other female organs have estrogen receptors and when exposed to estrogen, are stimulated to grow. When cells that have estrogen receptors become cancerous, the growth of these cancer cells can be increased by exposure to estrogen. The basis of hormonal therapy as a treatment for breast cancer is to block or prevent the cancer cells from being exposed to estrogen.
Removal of the source of estrogen production, the ovaries, is one effective approach to eliminating estrogen production in premenopausal women, and is commonly used in many countries. Another approach is to utilize drugs to block estrogen receptors and prevent the estrogen-stimulated growth of the breast cancer cells.
The role of hormone therapy among women with DCIS was evaluated in a clinical trial known as NSABP B-24. All women in the study had DCIS that was treated with lumpectomy and radiation therapy. Half the women were given the hormonal therapy tamoxifen and half were given a placebo. The primary results from the study indicated that tamoxifen reduced the risk of another breast cancer diagnosis.
Learn more about hormonal therapy.for breast cancer
Strategies to Improve Outcomes
The progress that has been made in the treatment of DCIS has resulted from doctor and patient participation in clinical studies. Future progress in the treatment of DCIS will result from continued participation in appropriate studies. Areas of active exploration to improve the treatment of DCIS include the following:
Attempts to identify patients who do not require radiation therapy: There have been attempts to identify patients who can be cured with breast-conserving surgery alone by examination of the characteristics of the DCIS. Improvements in this area could spare many patients the need for radiation therapy.
OncotypeDX: Test for Women with DCIS: This test provides information about the risk of cancer recurrence among women with DCIS that is treated with lumpectomy. The test evaluates the activity of certain genes in a sample of tumor tissue and generates a DCIS Score. The higher the score, the greater the risk of cancer recurrence. Having information about risk of recurrence may help guide decisions about post-surgery treatment of DCIS.
 Kerlikowske K. Epidemiology of ductal carcinoma in situ. Journal of the National Cancer Institute Monographs. 2010;41:139-41.
 Goodwin A, Parker S, Ghersi D, Wilcken N. Post-operative radiotherapy for ductal carcinoma in situ of the breast. Cochrane Database Syst Rev. 2009;4:CD000563.
 Allred DC, Anderson SJ, Paik S et al. Adjuvant tamoxifen reduces subsequent breast cancer in women with estrogen receptor-positive ductal carcinoma in situ: a study based on NSABP protocol B-24. Journal of Clinical Oncology. Early online publication March 5, 2012.
 Solin LJ, Gray R, Baehner FL et al. A Quantitative Multigene RT-PCR Assay for Predicting Recurrence Risk after Surgical Excision Alone without Irradiation for Ductal Carcinoma In Situ (DCIS): A Prospective Validation Study of the DCIS Score from ECOG E5194. Presented at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium. December 6-10, 2011. Abstract S4-6.