Overview of DCIS

Cancer of the breast is the most frequently diagnosed cancer in U.S. women, but it can also occur in men.* 

If you have been diagnosed with ductal carcinoma in situ (DCIS), which is considered a noninvasive breast cancer, you probably have many questions and concerns about treatment. This patient summary, which is based on the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines™) for breast cancer, will help you understand the best available treatments for DCIS. Talk with your doctor about these therapies so that together you can decide on a treatment plan that is right for you.

Background

Breast cancer is the most common cancer in women. Breast cancer usually occurs in the lobules of the breast, which is where milk is produced, or in the ducts that drain milk from the breast.  In the United States, breast cancer occurs most frequently in women who have gone through menopause, although it can occur at any age. 

Ductal carcinoma in situ (DCIS) is considered to be noninvasive breast cancer that occurs in the lining of the breast ducts.  The term "in situ" means “in place”; carcinoma in situ refers to a very early stage of cancer that has not spread beyond the tissue in which it first developed.

Diagnosis, Grading, and Tumor Markers in DCIS

A breast lump, an abnormal mammogram, or abnormal results from an MRI or ultrasound each may suggest breast cancer, but only a biopsy of breast tissue can determine whether breast cancer is present.  

In addition to confirming a diagnosis of breast cancer, the biopsy sample provides your doctor with information about:

• Where the breast the cancer began
• Whether the cancer is noninvasive (localized in site of origin) or invasive (has spread through the wall of the duct into surrounding tissues)
• The grade of the tumor cells (that is, how much the cancer cells resemble healthy cells under a microscope; generally, grade 1 breast cancer grows slowly, while grade 3 grows more quickly)
• Whether the estrogen receptor tumor marker is present in high levels in DCIS cells, which means you might be a candidate for hormone therapy (see Hormone Therapy for Breast Cancer Risk Reduction below).

DCIS is considered the earliest form of breast cancer and is often difficult to detect. Often no lump can be felt and women see no signs or symptoms with it, although a small number of women may feel a lump or experience discharge from the nipple. DCIS is most often found in an abnormal mammogram. 

Staging

Staging describes the extent or severity of the cancer. The stages of breast cancer are stage 0 or stages I through IV. Stage 0 breast disease is in situ disease. The significance of this is that in situ disease has not invaded breast tissue and thus cannot spread to other organs in the body. See the Cancer Staging Guide. 

Treatment for DCIS

The primary treatment for DCIS is surgical removal of the affected area in the breast tissue. The purpose of this is to prevent the DCIS from growing and becoming invasive. The amount of surgery depends on the amount of breast tissue that has DCIS, the size of the breast, other health or physical factors, and your personal preferences. The options for surgery are lumpectomy and mastectomy. If you choose lumpectomy, several weeks of radiation therapy will also probably be part of your treatment. Lumpectomy with radiation and mastectomy are equally effective. Generally, treatment for DCIS is curative.

When choosing between lumpectomy and mastectomy, you and your doctor must consider:

• The size of the area of DCIS: a mastectomy may be needed to treat larger areas of DCIS or DCIS that is widespread in the breast; smaller areas of DCIS are often treatable with lumpectomy.
• The number of areas of DCIS: mastectomy is often the best choice when DCIS involves more than one area of the breast.
• Your personal preferences: some women are concerned with maintaining body image, whereas others want the whole treatment to be over as quickly as possible.  Talk with your doctor about what is important to you in selecting a treatment.

Lumpectomy

Although often no actual “lump” is felt or seen on the mammogram in DCIS, the term lumpectomy is used to describe the operation to remove just the area of DCIS and a small amount of healthy tissue around the outside of the tumor. Lumpectomy is followed in many cases by radiation therapy, which treats the breast area with high-energy beams to stop any remaining cancer cells from growing and dividing.
Unlike invasive cancer, DCIS does not require that lymph nodes be examined for the spread of the cancer.  The structures in the breast are kept intact when lumpectomy is performed. 

However, in rare cases, an area of invasive cancer is found when the removed lump is examined by a pathologist after surgery. Should this happen, your doctor will then perform a sentinel lymph node biopsy to see whether cancer has spread to the lymph nodes. With a sentinel lymph node biopsy, only the lymph nodes closest to the primary tumor are removed, as these are where the cancer is likely to have spread. Therefore, only a few lymph nodes are removed, which causes fewer side effects than more extensive surgery. The procedure is described more fully in the next section on mastectomy. 

Mastectomy

Some women who have DCIS involving more than one area of the breast will require a total mastectomy. Total mastectomy is removal of the entire breast, but not the  lymph nodes  under the arm.  Breast reconstruction is an option for many women after they have undergone mastectomy (see  Breast Reconstruction After Mastectomy ).

If you are treated for DCIS with total mastectomy, a sentinel lymph node biopsy may be performed at the same time so your doctor can determine whether cancer has spread to the lymph nodes.  This is not because DCIS spreads to lymph nodes, but because when DCIS is found on the initial tissue biopsy, there is a small chance that invasive cancer will also be found in the larger amount of tissue removed during surgery. Because a total mastectomy makes it impossible to perform sentinel node biopsy later, the procedure is done during the total mastectomy in case the woman is one of the very few in whom invasive cancer is also found.

When a sentinel lymph node biopsy is performed, a blue dye and/or a radioactive substance, or tracer, is injected into the tumor at the time of surgery. This dye and tracer travel through the lymphatic system to the armpit lymph nodes.  They are trapped in the first lymph nodes they come to, the same nodes that cancer could go to. These nodes are shown at surgery by the blue color or the presence of radioactivity and are removed and then evaluated for the presence of cancer.

If no breast cancer is found in the sentinel node(s), then no additional lymph node surgery is necessary.

If you are a candidate for this procedure, ask your doctor whether the team that will be performing the surgery has performed many others, because the accuracy of the test is directly related to the team’s experience. The most experienced surgical teams can usually be found at large or highly specialized cancer centers.

Breast Reconstruction After Mastectomy

If you have a mastectomy to treat DCIS, you may have surgery to reconstruct the breast immediately after the mastectomy or in a separate operation at a later time. Reconstruction may be performed using tissue removed from the abdomen or another part of the body, using an artificial implant, or using a combination of the two methods.

Breast reconstruction surgery has potential risks and complications. Doctors usually recommend it only for otherwise healthy women who do not have certain conditions (such as diabetes) or who do not smoke, because women with these conditions have an increased risk for experiencing complications from the surgery. If you think the procedure may be right for you, ask your doctor to refer you to a plastic surgeon before you schedule the mastectomy.

Radiation Therapy

After lumpectomy for DCIS, there is a small chance that microscopic amounts of cancer cells remain in duct tissue that was not removed during surgery. These could grow over time and require treatment.  Radiation therapy, which uses high-energy beams, kills these remaining cancer cells in most cases and dramatically reduces the chance that the cancer will come back.

Radiation is used in most women treated with lumpectomy for DCIS, usually for several weeks after surgery.  Radiation therapy is not used for women who have had a mastectomy for DCIS.

In some cases, the likelihood of cancer regrowth in the breast after lumpectomy for DCIS is very low, even without radiation.  Some women who are considered to have a low risk of DCIS returning, such as those older than 60 years with small, low-grade tumors that have been completely removed by lumpectomy, may not require radiation therapy.  Before deciding whether to have radiation therapy for DCIS, it is important for you to discuss your specific risks with your doctor. 

Most women tolerate radiation therapy very well. It may cause some redness and swelling of the breast; however, most of this disappears after the radiation is finished.  In some women who have undergone lumpectomy and radiation therapy, the breast becomes firmer or the size of the breast decreases. These changes may be either temporary or permanent.

Chemotherapy 

You will not be given chemotherapy for DCIS.  It is not necessary for this very early stage of breast cancer.   

Hormone Therapy for Breast Cancer Risk Reduction

The hormone estrogen can stimulate the growth of certain breast cancers that have receptors for estrogen, or are estrogen receptor–positive.  Hormone therapy blocks the hormonal stimulation of breast cancer tumor growth.  There are two separate roles for hormonal therapy in DCIS:

• To reduce the very small possibility that DCIS might come back in the same breast if you have been treated with lumpectomy.  You may be a candidate for therapy with tamoxifen to reduce your risk of the cancer coming back, especially if it tested positive for the estrogen receptor. Tamoxifen blocks the effects of estrogen on tumor cells.
• To reduce your risk of developing a new breast cancer in either breast, regardless of whether your DCIS had estrogen receptors (risk-reduction therapy). 

If you are considering risk-reduction therapy, tamoxifen may reduce your risk of developing cancer in either breast in the future, depending on your health and past medical conditions. Tamoxifen can be taken by pre- and postmenopausal women.

Ask your doctor about the benefits and side effects of hormone therapy. It is important to let your doctor know whether you are taking any other medications because they might interact with your hormone therapy. 

Side effects associated with hormone therapy include hot flashes, a slightly increased risk for blood clots and developing cancer of the uterus. If you are taking tamoxifen, you should call your doctor if you experience abnormal uterine bleeding and symptoms/signs of a blood clot, such as swelling and pain in a leg or arm.

Hormone therapies are usually taken as pills and are generally given for about 5 years. It is important that you do not stop such therapy without consulting with your doctor because these drugs are more effective when taken for long periods of time.

Life After Treatment for DCIS

After completion of treatment for DCIS, you will begin a period called follow-up. During this period, you will visit your doctor every 6 to 12 months to ensure your continued good health.  These visits to your doctor will give you a chance to ask questions and share your concerns. You will need an annual mammogram to ensure that if you develop a new breast cancer, it can be found and treated at an early stage. 

If you are taking tamoxifen, you will also need to see your gynecologist for an annual exam.  If you experience any abnormal vaginal bleeding or plan to have surgery at any time for any other reason, let your doctor know so that proper precautions can be taken. 

  *Less than one percent of these cases occur in men. Because this summary is focused only on women’s breast cancer, men in search of information about male breast cancer may want to begin by visiting the National Institutes of Health's page on male breast cancer.