Ductal Carcinoma in Situ (DCIS)

As more women have gotten mammograms on a regular basis, DCIS has been found far more often. DCIS is a noninvasive precancer. It is not life threatening. If you have DCIS, it means that you have abnormal cells in the lining of a duct. While virtually all invasive cancer begins as DCIS, not all DCIS will go on to become an invasive cancer. An invasive cancer is one that has the potential to metastasize (spread). Right now we have no way to determine which DCIS will go on to become invasive cancer and which will not. That’s why doctors recommend DCIS be treated.

DCIS is a noninvasive precancer which is not life threatening

DCIS appears as microcalcifications on a mammogram. When these microcalcifications are seen, it is recommended that a woman have a core biopsy or a wire localization biopsy. This will determine whether you actually have DCIS. If you do, the next step should always be to have another mammogram to see if the biopsy has gotten rid of all the microcalcifications, as no matter how thorough your surgeon has been, there still may be a few remaining. If the diagnosis is DCIS, make sure your pathology report includes information about the grade, presence of necrosis, margin, and estrogen receptor. This information is needed to determine how to treat the DCIS.

How is DCIS treated?

The options for treating DCIS are: lumpectomy, lumpectomy and radiation, a combination of those with tamoxifen, or mastectomy. You don’t have to rush into any one treatment because your doctor or your friend or anyone else says you should. It’s your breast, and your life. Take the time to decide what’s best for you.


The goal of treating DCIS is prevention. As long as the precancer is completely removed, it can neither come back nor become invasive. Currently not all doctors are in agreement about the best way to treat DCIS. Most women undergo breast conservation surgery, a lumpectomy. However, if the DCIS is throughout the breast, a mastectomy will probably be necessary. There is no reason to remove lymph nodes for small areas of DCIS since precancer can’t spread at this stage. But if the lesions are big (greater than 5cm), some experts think they may hide microinvasion and recommend removing the lymph nodes as well.

Learn more about surgery here.


It is recommended that most women with DCIS receive radiation following a lumpectomy. Radiation will not increase your chances of survival (since DCIS is not life-threatening) but it will reduce your risk of having the DCIS return as DCIS or invasive breast cancer. The National Comprehensive Cancer Network developed a patient-friendly book that explains current guidelines for treating DCIS. 

Learn more about radiation here.

Hormone Therapy

Since DCIS is not capable of spreading, there is no reason to use chemotherapy. However, if the DCIS is ER-positive you will need to consider whether you want to take tamoxifen for five years to reduce your risk of a recurrence. The decision to take tamoxifen for DCIS is a difficult one for many women, as the benefits from taking it are small and have to be weighed against the risks associated with the drug as well as any side effects you may experience.

Learn more about hormone therapy here.

If you have a family history of breast cancer in addition to DCIS and you want to understand more about whether your family history may contribute to your breast cancer risk, you should make an appointment with a genetic counselor to discuss testing for the hereditary breast cancer gene mutations, called BRCA1 and BRCA2, which put women at higher risk for breast and ovarian cancer. The National Cancer Institute and the National Society of Genetic Counselors can help you locate a genetic counselor near you. Under the Affordable Care Act, genetic counseling and testing are covered for high-risk women.

If you decide to have genetic testing and if you are found to carry a BRCA genetic mutation your doctor may suggest that you consider a bilateral prophylactic mastectomy (removal of both breasts). This will reduce the chance of getting breast cancer by about 95 percent. The surgery is recommended if you have a strong family history of the disease. It is not recommended for women just because they have had a diagnosis of DCIS, however, some women do choose this option.

Frequently Asked Questions


Should I have my DCIS tested to see if it is HER2-positive?

DCIS is not tested for HER2 for two reasons: one, DCIS is more likely than invasive cancer to be HER2+ (we don’t know why); two, DCIS is not treated with HER2-targeted therapies, so testing DCIS for HER2 would not influence treatment choices.

I was diagnosed with DCIS. Should I take tamoxifen for five years?

If your DCIS is ER-positive, your doctor may recommend that you take tamoxifen.

Tamoxifen began to be routinely offered to women for DCIS in 1999, after researchers reported the results of a study that investigated whether adding tamoxifen to DCIS treatment had additional value. (The findings were confirmed with additional follow-up data in 2005.) The study randomized 1,804 women who had been treated with surgery followed by radiation for DCIS to tamoxifen or a placebo for five years. After following the women for five years, the researchers found that:

  • Forty women in the placebo group and 23 in the tamoxifen group developed subsequent invasive cancers in the treated breast. Statistically, tamoxifen reduced the chance of developing invasive cancer from 4.2 percent to 2.1 percent.
  • There were 47 noninvasive recurrences (more DCIS) in the placebo group and 40 in the tamoxifen group. Statistically, tamoxifen lowered the rate of noninvasive recurrences (new ones or DCIS left over from earlier treatment) from 5.1 percent to 3.9 percent.
  • Thirty-six cancers (noninvasive and invasive combined) developed in the opposite breast in the placebo group while 18 developed in the tamoxifen group. Statistically, tamoxifen lowered the rate of developing cancer in the opposite breast from 3.45 percent to 2.0 percent.
  • There were 7 recurrences in the placebo group and 3 recurrences in the tamoxifen group in the nodes, chest wall, or elsewhere in the body (metastases). Although the recurrence rate was less than half as great in the tamoxifen group, the numbers are too small to be statistically significant.
  • There were 6 deaths from breast cancer (a very rare event for DCIS) in the placebo group, including 2 from cancers in the same breast as the original DCIS. In comparison, there were 4 deaths in the tamoxifen group, including 3 that were attributed to cancers in the treated breast.
  • Overall, tamoxifen reduced the risk of any breast-related event (recurrent invasive disease, noninvasive disease, second cancers in the opposite breast, and metastasis) from 13.4 percent to 8.2 percent.
  • Side effects included 2 cases of phlebitis (inflammation of a vein) in the placebo group and 9 in the tamoxifen group, with 1 nonfatal pulmonary embolism (obstruction of a blood vessel in the lungs, usually due to a blood clot) in the placebo group and 2 in the tamoxifen group. In addition, there were 36 cases of uterine cancer in the tamoxifen group and 15 in the placebo group, although there were no uterine-cancer deaths. There was also about a 10 percent higher incidence of hot flashes, fluid retention, and vaginal discharge in the tamoxifen group than the placebo group.

Choosing whether to take tamoxifen to treat DCIS is obviously a complex issue. The advantages are small, but then so are the risks. Each woman will probably evaluate these risks and benefits differently. The only “right” choice is the choice that you feel is right for you.

In making your decision, you may find the National Comprehensive Cancer Network Clinical Practice Guideline for Stage 0 Breast Cancer helpful.

Can I take raloxifene (Evista) instead of tamoxifen?

No—and here’s why. Raloxifene (brand name Evista) is approved for use as a treatment to reduce cancer risk in high-risk women. It is not approved for use as a treatment for DCIS or invasive breast cancer. Sometimes it is offered to postmenopausal women who cannot tolerate the side effects of tamoxifen, but this is not done routinely.

I was diagnosed with grade II/III DCIS. Do I need to be treated now? Couldn’t I wait a year and see what happens?

I understand why you could think that this might be a “wait and see” type of situation, given that most DCIS does not go on to become invasive cancer.

But I—along with most doctors —would not recommend that you wait for a year to be treated. Not all DCIS is the same and your grade of DCIS—ll/lll is more likely to go on to become invasive cancer. Many people would estimate the risk for this type of DCIS to be between 50% and 60%, rather than 30%.

The data that we have about DCIS going on to become invasive cancer comes from women that were misdiagnosed, and they were more likely to have a lower grade DCIS. Right now, we have no way to definitively say which women with DCIS will go on to have invasive cancer and which will not. One day, we probably will. And when that happens, we will be able to tell some women that they can safely avoid treatment. But until then, it is recommended that all women who have been diagnosed with DCIS be treated.

I had a mastectomy because I had extensive DCIS in my right breast. Do I still need to take tamoxifen?

Since your ductal carcinoma in situ (DCIS) was treated with a mastectomy, tamoxifen wouldn’t be used to reduce your chance of a local recurrence. Rather, it would be used to reduce your risk of developing a breast cancer in the opposite breast—in other words, for risk reduction. It is important to remember, however, that the risk of DCIS in the other breast is only 10 percent over your lifetime. Also, we do not have any data that show a survival benefit from taking the tamoxifen, only a benefit in reducing the risk of the development of disease. Ultimately, only you can determine what is right for you and whether the benefits of tamoxifen outweigh the risks and side effects.

I was recently diagnosed with DCIS. My surgeon said that, in addition to removing the duct, he needs to remove my nipple. Is this really necessary?

The answer is a resounding “maybe.”

I can understand why you would want to keep your nipple, but, unfortunately, sometimes this just can’t be done. The clinical trials that looked at the effectiveness of nipple preservation when women have tumors located directly under the nipple found an unacceptably high rate of cancer recurrence in the nipple—and this is something you just don’t want to risk. The problem is that there is a lot of ductal tissue that comes up into the nipple, and that ductal tissue may contain cancer cells. This is why when the tumor is right under the nipple it is safer to remove the nipple and reconstruct it. If the ductal carcinoma in situ (DCIS) is not located right under the nipple, then the nipple often can be preserved.

You may want to get a second or third opinion from another surgeon as to the location of the DCIS and the need for nipple removal before scheduling your surgery.

My pathology report showed extensive DCIS. It also looked like I had micrometastasis. What should I do?

The micrometastasis was discovered because your surgeon performed an axillary lymph node dissection. A surgeon typically performs a lymph node dissection for ductal carcinoma in situ (DCIS) when there is extensive DCIS (like you had) or when a patient has a high-grade DCIS. When DCIS is high-grade, there are many dead cells in the duct, and the cells that are alive are very aberrant. In this situation there is a higher chance that microinvasion—a spot where the DCIS has crossed the line to invasion—has occurred.

It can be tricky to diagnose micrometastases in the sentinel node. Most likely your micrometastasis is due to cells that were displaced during surgery as opposed to an actual spread of cancer cells from the DCIS, especially if there was no invasion outside the duct. However, the only way to know this for sure is to have an expert in breast pathology determine if it is truly micrometastasis or if it is a displaced cell. This is why it is very important that you get a second opinion from a specialist in breast pathology. Displacement of cells is not the same as having metastasis, and it does not require the treatment with chemotherapy that you would need if metastasis truly were present.

If there are indeed multiple areas of micrometastasis, some doctors would recommend chemotherapy because there would be concern that an invasion had been missed.

Your next step should be to get a second pathology opinion. This second opinion should not come from a general pathologist but from a specialist in breast pathology. To get a second pathology opinion, you will need to have the hospital where you had your surgery performed send your slides to the pathologist you have selected. You also may want to consider being seen at a multidisciplinary breast care center where you could not only bring your pathology slides and breast films for review, but be seen by a breast specialist, medical oncologist, and radiation oncologist. They would review your pathology slides and mammography images and then discuss as a group how they think you should proceed.

To find this type of program in your area, you can contact the university-based hospital nearest you, the American Cancer Society, a local breast cancer support group, or one of the National Cancer Institute’s Comprehensive Cancer Centers.

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