Ductal carcinoma in situ (DCIS) is a type of noninvasive breast cancer, found when the cancer is still in the early stages. Treatments for DCIS often work very well to keep the cancer under control and prevent it from spreading. Most people who are diagnosed with this cancer achieve complete remission — their cancer disappears and doesn’t return.
Ductal carcinoma in situ develops in the cells that make up the milk ducts within the breast. During DCIS, these cells undergo changes that make them grow abnormally.
There are several different types of breast cancer. Most are invasive — the cells within a breast tumor begin growing into nearby normal tissue. However, ductal carcinoma in situ is noninvasive. The cancerous cells remain in one location. In fact, the term “carcinoma in situ” refers to a group of abnormal cells that have not spread beyond the place where they first formed. However, DCIS may become invasive if it is left untreated. If DCIS transforms into invasive breast cancer, it may metastasize (spread to other parts of the body).
For most people, DCIS does not cause any symptoms. Occasionally, a person with this cancer may notice a small lump in their breast. DCIS may also lead to bloody discharge from one nipple.
Around 4 out of 5 people find out that they have DCIS after they receive a mammogram. Mammograms are imaging tests that use X-rays and can be used to find abnormalities within the breast. When used as a screening tool, these tests can help detect breast cancer early. The federal Centers for Disease Control and Prevention (CDC) recommends that women who are at least 50 years old should undergo regular screening mammograms. Some experts recommend that women should begin receiving mammograms in their 40s. Your doctor can help you better understand when to undergo a breast cancer screening, based on your personal risk of developing breast cancer.
Mammograms play an important role in diagnosing DCIS. They can show clusters of breast cancer cells. However, mammograms can also pick up other benign (non-cancerous) conditions. A doctor can’t make a definitive diagnosis of breast cancer based on a mammogram alone — other tests are also needed.
If a screening mammogram uncovers an abnormal finding, some doctors recommend a diagnostic mammogram. This test can get a view of the breast tissue from different angles. A diagnostic mammogram can give doctors a better idea of whether there may be a problem and if further diagnostic tests are needed.
Abnormal areas of the breast need to be further studied with a biopsy, in which a small sample of tissue is removed. There are a couple of different types of breast biopsy. A fine needle aspiration biopsy uses a very small needle to take out a tiny sample of cells. A core needle biopsy uses a larger needle to remove several slightly larger tissue samples. Some people who need a biopsy may undergo surgery to remove a larger section of breast tissue.
After a biopsy, laboratory tests can uncover several pieces of information, including:
This information helps doctors estimate a person’s prognosis (outlook) and know which treatments are likely to work best.
Ductal carcinoma in situ treatment usually involves surgery, which may be followed by radiation therapy or hormone therapy. These treatments are usually very effective at eliminating breast cancer. The exact treatments you receive depend on your age, personal preferences, tumor size, cancer grade, and molecular subtype.
People with DCIS usually don’t receive chemotherapy. Chemotherapy drugs are useful for reaching cancer cells located in one or many places throughout the body. However, DCIS is a precancerous condition.
There are two main surgical options for DCIS. One possible surgery is a lumpectomy or breast-conserving surgery. During this surgery, the doctor takes out the tumor and a small amount of surrounding normal tissue. This means that a person still has some normal breast tissue remaining after surgery.
People with DCIS throughout the breast may need to get a mastectomy. In this surgery, almost all of the breast tissue needs to be removed. A mastectomy may be necessary for people with large or multiple tumors or tumors that are hard to remove. Additionally, people who can’t go through radiation treatments may need to have a mastectomy. This may include people who are pregnant, have certain health conditions, or have previously gone through radiation therapy in the same places.
Lumpectomies and mastectomies may be followed by breast reconstruction surgery, in which the breast tissue is rebuilt.
Surgery for DCIS may occasionally include a sentinel lymph node biopsy. During this procedure, a surgeon removes one or a couple of lymph nodes. Breast cancer cells sometimes spread to lymph nodes near the breast or armpit, so this surgery can help ensure all cancer cells are removed and detect whether cancer has begun to spread.
Most people who undergo a lumpectomy also need to go through radiation treatments. During radiation therapy, a person is exposed to high-energy beams or particles that damage and kill cancer cells.
There are a few different types of radiation therapy. Most people with DCIS receive external beam radiation therapy, in which a large machine directs beams toward the breast from different directions. Other types of radiation treatments are also being studied in clinical trials. Some newer techniques can more accurately target the tumor location, rather than delivering radiation to the entire breast. Additionally, some types of radiation therapy, called brachytherapy, involve temporarily placing small amounts of radioactive material directly inside of the breast tissue.
Some DCIS tumors are hormone receptor-positive — the cancer cells contain either estrogen receptor (ER) or progesterone receptor (PR). These proteins, called hormone receptors, allow the cancer to grow. Hormone therapies such as Nolvadex (tamoxifen) can block ER and PR, helping reduce the chances of having a relapse (that is, having the cancer returning). These treatments are begun after surgery, and often taken for five years.
People with DCIS have a very good outlook. About 98 percent of people with this cancer survive 10 years or more after being diagnosed.
People with DCIS have a higher risk of developing breast cancer again in the future. Some people who have been treated with DCIS will experience a relapse. The chances of relapse partly depend on which treatment options a person chooses. For example, people who undergo a lumpectomy alone have a 25 percent to 30 percent chance of experiencing a relapse. People who have a lumpectomy followed by radiation therapy have up to a 15 percent chance of relapse.
Those who are diagnosed with high-grade (faster-growing) DCIS are more likely to have a relapse than those with low-grade DCIS. They are also more likely to have invasive cancer.
After DCIS is treated, a person will continue to have follow-up visits with their doctor to make sure that healing is progressing properly and to look for signs of cancer. Many people who have had breast cancer have physical exams and screening tests once or twice per year. Ask your doctor how often you should be having follow-up visits and what tests you should be receiving.
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