Ductal carcinoma in situ (DCIS) is breast cancer, but it is non-invasive (stage 0). “Ductal” means “related to the milk ducts” and “in situ” means "in place." With DCIS, the cancer cells are contained within the milk ducts. Because the cancer cells have not invaded nearby breast tissue, DCIS is not invasive breast cancer.
Image source: National Cancer Institute (http://www.cancer.gov)
It is estimated that there will be about 55,000 new cases of DCIS diagnosed among women in the U.S. in 2013.1
Although DCIS is not invasive breast cancer, it can sometimes turn into invasive breast cancer. After treatment, there is still a small chance that cancer will return to the breast. About half the time, it returns as DCIS and about half the time it returns as invasive breast cancer.2 Treatment for DCIS is similar to treatment for invasive breast cancer. It involves surgery, with or without radiation therapy, and for some women, hormone therapy. One difference in treatment is that chemotherapy is not given for DCIS. With treatment, prognosis is excellent.
The first step in treating DCIS is surgery to remove it. Depending on how far the DCIS has spread within the milk ducts, surgery can be either lumpectomy or mastectomy. In most cases, surgery does not include the removal of any lymph nodes. For women who have the option, lumpectomy plus radiation therapy and mastectomy are equally effective in lowering the risk of invasive breast cancer and DCIS recurrence.3 Learn more about lumpectomy and mastectomy.
After lumpectomy Lumpectomy for DCIS is usually followed by radiation therapy. Overall survival appears to be similar for women with DCIS who have lumpectomy with or without radiation therapy.4-3 However, radiation therapy after lumpectomy can:2,4-8
Select older women with DCIS may be candidates for lumpectomy without radiation therapy. This may be an option when:2,10
Radiation therapy is not given to women treated with mastectomy for DCIS.
Learn more about radiation therapy.
Find a summary of research studies on lumpectomy plus radiation therapy in the treatment of DCIS.
The hormone therapy drug tamoxifen can be used to treat estrogen receptor-positive DCIS.
The use of hormone therapy with aromatase inhibitors (instead of tamoxifen) for DCIS is under study. Although aromatase inhibitors are used to treat estrogen receptor-positive invasive breast cancer, data on their use in treating DCIS are limited. So, at this time, tamoxifen is more commonly used to treat estrogen receptor-positive DCIS. After lumpectomy
Women who are treated with lumpectomy plus radiation therapy for estrogen receptor-positive DCIS, however, may consider taking tamoxifen for five years.2 Although tamoxifen has not been shown to increase overall survival for DCIS, studies have shown tamoxifen can:7-8
Tamoxifen is not usually recommended for women who have a mastectomy for estrogen receptor-positive DCIS. These women have an excellent prognosis with a low risk of invasive breast cancer or DCIS recurrence, so the benefit of tamoxifen is likely very small.
Learn more about hormone therapy.
Find a summary of research studies on tamoxifen in the treatment of DCIS.
Among women with the same treatments for DCIS, race and ethnicity do not seem to impact rates of DCIS recurrence or invasive breast cancer.9
The good news is that most DCIS will not progress to invasive breast cancer.11 However, health care providers cannot yet predict which cases of DCIS will turn into invasive breast cancer and which will not. So, every case of DCIS is treated. Unfortunately, this means some women are “over-treated” for DCIS. They get little benefit (beyond peace of mind) from treatment because they would never develop invasive breast cancer with or without treatment for DCIS.
Choosing the appropriate treatment for DCIS is a major research challenge. Researchers are studying ways to identify the cases of DCIS most likely to turn into invasive breast cancer. This would allow treatment to be targeted to those who are at higher risk.
If you have been diagnosed with DCIS, discuss the benefits and risks of joining a clinical trial with your health care provider. BreastCancerTrials.org in collaboration with Susan G. Komen for the Cure® offers a custom matching service that can help you find a clinical trial that fits your health needs.
In conclusion, Dr. Lori Pierce, Vice Provost for Academic and Faculty Affairs and Professor of Radiation Oncology at the University of Michigan, says “this article has summarized nicely the major challenges facing breast cancer patients and their physicians in the management of ductal carcinoma in situ (DCIS). DCIS is not an invasive disease but can progress to invasive breast cancer, and potentially impact survival, in a significant number of women if not adequately treated when diagnosed. And we know that for those patients treated with lumpectomy, radiation to follow will reduce the chance of DCIS returning and/or invasive disease developing by at least 50%. We also know, however, that in some patients, the likelihood that DCIS will progress to invasive disease is very low even in the absence of treatment. Unfortunately, we have not found a reproducible way to predict those who need to be treated and those who don’t but many researchers are working on this very question. For now, clinicians should have detailed discussions with patients diagnosed with DCIS regarding the pros and cons of treatment to help them make well-informed decisions regarding therapeutic options and outcomes.”
In the past six years (2007-2012) Komen has funded 29 grants that focus on DCIS. Most of these projects focus on the basic biology of how DCIS develops or on indentifying biomarkers that predict which women with DCIS will go on to develop invasive breast cancer. Eleven of these grants support clinical trials that include women with DCIS.
Posted February 28, 2013