DCIS (ductal carcinoma in situ) is a non-invasive breast cancer. In DCIS, the abnormal cells are contained in the milk ducts. It is called “in situ” (which means "in place") because the cells have not left the milk ducts to invade nearby breast tissue.
DCIS is also called intraductal (within the milk ducts) carcinoma. You may also hear the terms “pre-invasive” or “pre-cancerous” to describe DCIS.
DCIS is non-invasive, but without treatment, the abnormal cells could turn into invasive cancer over time. Left untreated, about 40 to 50 percent of DCIS cases may progress to invasive breast cancer . (These numbers are estimates.) Higher grade DCIS may be more likely than lower grade DCIS to turn into invasive cancer if left untreated.
At this time, health care providers cannot predict which cases of DCIS will progress to invasive breast cancer and which will not. Because DCIS might turn into invasive breast cancer, almost every case of DCIS is treated.
Surgery (with or without radiation therapy) is recommended for the treatment of DCIS. After surgery and radiation therapy, some women may take hormone therapy.
Learn about recommended treatments for DCIS.
Learn about the risk of invasive breast cancer after treatment for DCIS.
Although the exact treatment for DCIS varies from person to person, guidelines help ensure quality care. These guidelines are based on the latest research and the consensus of experts.
The National Comprehensive Care Network (NCCN) and American Society of Clinical Oncology (ASCO) are two respected organizations that regularly update and post their guidelines online. The National Cancer Institute (NCI) also has overviews of treatment options.
For more information on treatment for DCIS, visit the National Comprehensive Cancer Network (NCCN) or the American Society for Clinical Oncology (ASCO).
With treatment, prognosis for DCIS is usually excellent.
Surgery is the first step in treating DCIS. It removes the abnormal tissue in the breast. Depending on how far the DCIS has spread within the milk ducts, surgery can be either mastectomy or lumpectomy.
If DCIS has spread throughout the ducts, affecting a large part of the breast, a total (simple) mastectomy will be done. In a total mastectomy, the surgeon removes the entire breast, but no other tissue or lymph nodes.
If there is little spread of DCIS within the ducts, a choice can be made between mastectomy and lumpectomy. With lumpectomy, the surgeon removes only the abnormal tissue, but the rest of the breast is left intact. Lymph nodes are not usually removed.
Overall survival is the same for women with DCIS who have mastectomy and those who have lumpectomy (with or without radiation therapy) .
In the U.S., most women with DCIS choose lumpectomy followed by radiation therapy .
Learn more about mastectomy and lumpectomy.
Radiation therapy is not given to women who are treated with mastectomy for DCIS.
Lumpectomy for DCIS is usually followed by radiation therapy to lower the risk of [2-8]:
Select women with smaller, lower grade DCIS and clean surgical margins, may be able to have lumpectomy without radiation therapy [2,9].
Overall survival is the same for women with DCIS who have lumpectomy with or without radiation therapy [2,4].
Learn more about radiation therapy.
For a summary of research studies on lumpectomy plus radiation therapy in the treatment of DCIS, visit the Breast Cancer Research Studies section.
The National Comprehensive Cancer Network (NCCN) recommends women who are treated with lumpectomy plus radiation therapy for estrogen receptor-positive DCIS consider taking tamoxifen for five years . Studies have shown tamoxifen can lower the risk of [10-12]:
Tamoxifen is not usually recommended for women who have a mastectomy for DCIS. These women have an excellent prognosis with a very low risk of DCIS recurrence or developing breast cancer in the opposite breast, so the benefit of tamoxifen is likely very small.
Learn more about tamoxifen.
Learn more about factors that affect treatment options.
For a summary of research studies on tamoxifen as a treatment for DCIS, visit the Breast Cancer Research Studies section.
The use of aromatase inhibitor hormone therapy drugs are under study for the treatment of estrogen receptor-positive DCIS.
Learn more about aromatase inhibitors.
Learn more about emerging areas in the treatment of DCIS.
After treatment for ductal carcinoma in situ (DCIS) there is still a small chance DCIS could recur (return) or invasive breast cancer could develop. These risks are higher with lumpectomy (also called breast conserving surgery) plus radiation therapy than with mastectomy .
However, overall survival is the same after either treatment . With close follow-up, invasive breast cancer is usually caught early and can be treated successfully.
In 2013, the Institute of Medicine (IOM) released a set of recommendations (below) on improving cancer care in the U.S. The report Delivering High-Quality Cancer Care: Charting a New Course for a System in Crisis recommends improvements to fix shortcomings that add cost and burden to cancer care. Susan G. Komen was one of 13 organizations sponsoring this study.
The report identified key ways to improve quality of care:
Read the full report.
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*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date at this time.
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