Ductal carcinoma in situ (DCIS) is the presence of abnormal cells inside a milk duct in the breast.
DCIS is considered the earliest form of breast cancer. DCIS is noninvasive, meaning it hasn't spread out of the milk duct to invade other parts of the breast.
DCIS is usually found during a mammogram done as part of breast cancer screening or when there is another concern with a woman's breast. Because of increased screening with mammograms, the rate at which DCIS is diagnosed has increased dramatically in recent years.
While DCIS isn't life-threatening, it does require treatment to prevent the condition from becoming invasive. Most women with DCIS are effectively treated with breast-conserving surgery and radiation.
DCIS doesn't cause any signs or symptoms in most cases. However, DCIS can sometimes cause signs and symptoms, such as:
A breast lump
Bloody nipple discharge
DCIS is usually found on a mammogram and appears as small clusters of calcifications that have irregular shapes and sizes.
When to see a doctor
Make an appointment with your doctor if you notice a change in your breasts, such as a lump, an area of puckered or otherwise unusual skin, a thickened region under the skin, or nipple discharge. Contact your doctor to have it evaluated.
Ask your doctor when you should consider breast cancer screening and how often it should be repeated. Most groups recommend routine breast cancer screening beginning in your 40s. Talk with your doctor about what's right for you.
It's not clear what causes DCIS. DCIS forms when genetic mutations occur in the DNA of breast duct cells. The genetic mutations cause the cells to appear abnormal, but the cells don't yet have the ability to break out of the breast duct.
Researchers don't know exactly what triggers the abnormal cell growth that leads to DCIS. It's likely that a number of factors may play a part, including genes passed to you from your parents, your environment and your lifestyle.
Factors that may increase your risk of DCIS include:
Personal history of benign breast disease, such as atypical hyperplasia
Family history of breast cancer
First pregnancy after age 30
Taking combination estrogen-progestin hormone replacement therapy for more than three to five years after menopause
Genetic mutations that increase the risk of breast cancer, such as in the breast cancer genes BRCA1 and BRCA2
Make an appointment with your doctor if you notice a lump or any other unusual changes in your breasts.
If you have already had a breast abnormality evaluated by one doctor and are making an appointment for a second opinion, bring your original diagnostic mammogram images and biopsy results to your new appointment. These should include your mammography images, ultrasound CD and glass slides from your breast biopsy.
Take these items to your new appointment, or request that the office where your first evaluation was performed send these items to your second-opinion doctor.
Here's some information to help you get ready for your appointment, and what to expect from your doctor.
What you can do
Write down your medical history, including any benign breast conditions with which you've been diagnosed. Also mention any radiation therapy you may have received, even years ago.
Note any family history of breast cancer, especially in a first-degree relative, such as your mother or sister.
Make a list of your medications. Include any prescription or over-the-counter medications, vitamins, supplements or herbal remedies you're taking. If you're currently taking or have previously taken hormone replacement therapy, share this with your doctor.
Ask a family member or friend to join you for the appointment. Just hearing the word "cancer" can make it difficult for most people to focus on what the doctor says next. Take someone along who can help absorb all the information.
Write down questions to ask your doctor. Creating your list of questions in advance can help you make the most of your time with your doctor.
Below are some basic questions to ask your doctor about DCIS:
Do I have breast cancer?
What tests do I need to determine the type and stage of cancer?
What treatment approach do you recommend?
What are the possible side effects or complications of this treatment?
In general, how effective is this treatment in women with a similar diagnosis?
Am I a candidate for tamoxifen?
Am I at risk of this condition recurring?
Am I at risk of developing invasive breast cancer?
How will you treat DCIS if it does return?
How often will I need follow-up visits after I finish treatment?
What lifestyle changes can help reduce my risk of a DCIS recurrence?
Do I need a second opinion?
Should I see a genetic counselor?
If additional questions occur to you during your visit, don't hesitate to ask.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to talk about in-depth. Your doctor may ask:
Have you gone through menopause?
Are you using or have you used any medications or supplements to relieve the symptoms of menopause?
Have you had other breast biopsies or operations?
Have you been diagnosed with any previous breast conditions, including noncancerous conditions?
Have you been diagnosed with any other medical conditions?
Do you have any family history of breast cancer?
Have you or your close female relatives ever been tested for the BRCA gene mutations?
Have you ever had radiation therapy?
What is your typical daily diet, including alcohol intake?
DCIS is most often discovered during a mammogram used to screen for breast cancer. If suspicious areas such as bright white specks (microcalcifications) that are in a cluster and have irregular shapes or sizes are identified on your mammogram, your radiologist likely will recommend additional breast imaging.
You may have a diagnostic mammogram, which takes views at higher magnification from more angles, to take a closer look at the microcalcifications to be able to determine whether they are a cause for concern and to evaluate both breasts.
If the area of concern needs further evaluation, the next step may be an ultrasound and breast biopsy.
Removing breast tissue samples for testing
To collect breast tissue for testing, you may undergo one or more types of breast biopsy procedures:
Core needle biopsy. A radiologist or surgeon uses a hollow needle to remove tissue samples from the suspicious area, sometimes guided by ultrasound (ultrasound-guided breast biopsy). The tissue samples are sent to a lab for analysis.
Stereotactic biopsy. This type of biopsy also involves removing tissue samples with a hollow needle, but with the help of stereo images — mammogram images of the same area obtained from different angles — to find (localize) the area of concern.
Surgical biopsy (wide local excision or lumpectomy). If results from a core needle biopsy or stereotactic biopsy show areas of DCIS, you'll likely be referred to a surgeon to discuss your options for surgically removing a wider area of breast tissue for analysis.
A pathologist will analyze the breast tissue from your biopsy to determine whether abnormal cells are present and how aggressive those abnormal cells appear.
If your mammogram showed microcalcifications, the pathologist will examine the biopsy sample for those abnormalities.
Treatment of DCIS has a high likelihood of success, in most instances removing the tumor and preventing any recurrence.
In most cases, treatment options for DCIS include:
Lumpectomy and radiation therapy
In some cases, treatment options may include:
Lumpectomy and the drug tamoxifen
If you're diagnosed with DCIS, one of the first decisions you'll have to make is whether to treat the condition with breast-conserving surgery (lumpectomy) or breast-removing surgery (mastectomy).
Lumpectomy. Lumpectomy is surgery to remove the area of DCIS and a margin of healthy tissue that surrounds it.
The procedure allows you to keep as much of your breast as possible, and depending on the amount of tissue removed, usually eliminates the need for breast reconstruction.
Lumpectomy followed by radiation therapy is the most common treatment for DCIS.
Research suggests that women treated with lumpectomy have a slightly higher risk of recurrence than women who undergo mastectomy; survival rates between the two groups are very similar.
For older women with multiple medical conditions, lumpectomy plus tamoxifen therapy, lumpectomy alone or no treatment may be an option.
Mastectomy. For treating DCIS, a simple mastectomy — removing the breast tissue, skin, areola and nipple, and possibly the underarm lymph nodes (sentinel node biopsy) — is one option.
Breast reconstruction after mastectomy, if desired, can be performed in most cases.
Because lumpectomy combined with radiation is equally effective, simple mastectomy is less common than it once was for treating DCIS.
Most women with DCIS are candidates for lumpectomy. However, mastectomy may be recommended if:
You have a large area of DCIS. If the area is large compared with the size of your breast, a lumpectomy may not produce acceptable cosmetic results.
There's more than one area of DCIS (multifocal or multicentric disease). It's difficult to remove multiple areas of DCIS with a lumpectomy. This is especially true if DCIS is found in different sections — or quadrants — of the breast.
Tissue samples taken for biopsy show abnormal cells at or near the edge (margin) of the tissue specimen. There may be more DCIS than originally thought, meaning that a lumpectomy might not be adequate to remove all areas of DCIS. Additional tissue may need to be excised, which could require removing the breast (mastectomy) if the area of DCIS involvement is larger relative to the size of the breast.
If the area of DCIS is large, relative to the size of your breast, lumpectomy also may produce unacceptable cosmetic results.
You're not a candidate for radiation therapy. Radiation is usually given after a lumpectomy.
You may not be a candidate if you're diagnosed in the first trimester of pregnancy, you've received prior radiation to your chest or breast, or you have a condition that makes you more sensitive to the side effects of radiation therapy, such as systemic lupus erythematosus.
You prefer to have a mastectomy rather than a lumpectomy. For instance, you might not want a lumpectomy if you don't want to have radiation therapy.
Surgery for DCIS typically doesn't involve removal of lymph nodes from under your arm because it's noninvasive. The chance of finding cancer in the lymph nodes is extremely small.
If tissue obtained during surgery leads your doctor to think abnormal cells may have spread outside the breast duct or you are having a mastectomy, then a sentinel node biopsy or removal of some lymph nodes may be done as part of the surgery.
Radiation therapy uses high-energy beams, such as X-rays, to kill abnormal cells. Radiation therapy after lumpectomy reduces the chance that DCIS will come back (recur) or that it will progress to invasive cancer.
A type of radiation therapy called external beam radiation is most commonly used to treat DCIS.
Radiation is typically used after lumpectomy. But for some women, radiation may not be necessary. This might include those with only a small area of DCIS that is considered low grade and was completely removed during surgery.
The drug tamoxifen blocks the action of estrogen — a hormone that fuels some breast cancer cells and promotes tumor growth — to reduce your risk of developing invasive breast cancer.
Tamoxifen is effective only against cancers that grow in response to hormones (hormone receptor positive cancers).
Tamoxifen isn't a treatment for DCIS in and of itself, but it can be considered as additional (adjuvant) therapy after surgery or radiation in an attempt to decrease your chance of developing a recurrence of DCIS or invasive breast cancer in either breast in the future.
If you choose to have a mastectomy, there's less reason to use tamoxifen.
With a mastectomy, the risk of invasive breast cancer or recurrent DCIS in the small amount of remaining breast tissue is very small. Any potential benefit from tamoxifen would apply only to the opposite breast.
Discuss the pros and cons of tamoxifen with your doctor.