Ductal carcinoma in situ (DCIS) is cancer in your breasts’ milk ducts. It’s considered a noninvasive or pre-invasive cancer. This means that the cancer isn’t aggressive and doesn’t typically spread beyond your milk ducts. Lumpectomy and radiation are the most common treatments. DCIS is highly treatable, and the prognosis is excellent.
Ductal carcinoma in situ (DCIS) is a type of breast cancer where cancer cells line your milk ducts within one or both breasts. Milk ducts are tubes that carry milk from the lobes of your breasts to your nipples so you can breastfeed (chestfeed). The cancer is “in situ,” or situated (contained) inside of your milk ducts.
DCIS is also called noninvasive or pre-invasive breast cancer. This means that the cancer cells haven’t spread beyond the walls of your milk ducts. DCIS doesn’t typically metastasize, or spread to other organs in your body, as aggressive or invasive cancers do.
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DCIS is a common form of breast cancer among women and people assigned female at birth (AFAB), accounting for 20% to 25% of all new cancer diagnoses annually. Men and people assigned male at birth (AMAB) can get DCIS, but it’s rare (less than 0.1% of cancer diagnoses).
Cases of DCIS seem to have increased overall as more people have chosen to get yearly mammograms to screen for breast cancer. Also, mammography technology has improved to detect DCIS better. Increases in breast cancer diagnoses may sound like a negative, but it’s good news. Increased cases mean more people are getting diagnosed and treated early.
DCIS doesn’t generally cause symptoms. A few people with DCIS may notice a breast lump, itchy skin or nipple discharge (like blood). Still, more than 90% of DCIS is discovered by imaging procedures, like mammograms.
Scientists don’t know what causes abnormal cell growth in DCIS, but several factors may increase your risk. One of the most significant is age. If you’re a woman or AFAB, your chances of getting DCIS increase as you age, especially past age 30.
Other risk factors include:
Having a risk factor doesn’t mean you’ll get DCIS. For example, although a family history of breast cancer is a risk factor for DCIS, most people with DCIS don’t have family members with breast cancer. Risk factors are all about probability — what may increase your chance of developing a condition.
A mammogram can reveal abnormalities in your breast tissue that your healthcare provider can investigate further during a biopsy.
A mammogram uses a low-dose X-ray to take images of breast tissue. As old cells die and collect within your milk ducts, they leave tiny hardened calcium deposits called breast calcifications. Calcifications appear as a shadow or white spot on a mammogram. Abnormal calcifications may indicate abnormal cell growth, which may mean DCIS or other types of breast cancer.
Your healthcare provider may order an additional mammogram, called a diagnostic mammogram, if they find suspicious areas on a screening mammogram. A diagnostic mammogram provides more detailed views of your breast tissue. The procedure takes longer than a screening mammogram.
Mammograms used to detect DCIS include:
Your provider can perform a core needle biopsyto confirm that cancer cells are in your breast. With this procedure, your provider inserts a large needle into your breast to get a sample of the abnormal breast tissue. A medical specialist called a pathologist examines the cells in a lab for signs of cancer.
Imaging can help your provider locate the precise location of the abnormal tissue. They may use an ultrasound or an X-ray during your biopsy. A biopsy that uses an ultrasound is called an ultrasound-guided breast biopsy. A biopsy that uses X-rays, like a mammogram, is called a stereotactic breast biopsy.
DCIS is a highly treatable and curable stage 0 breast cancer. Healthcare providers classify cancer into stages from 0 to 4. To stage cancer, providers look at the original cluster of cancer cells (tumor) and determine where it’s located, the tumor’s size and if cancer cells have spread to other areas. The lower the number, the better chance for successful treatments.
Although DCIS is always stage 0, the tumor can be any size and may be located within several milk ducts inside of your breast. Regardless, the prognosis for DCIS with treatment is excellent.
Although DCIS isn’t an aggressive or fast-spreading cancer, it’s still important to receive treatment or have your healthcare provider monitor your condition closely. Some forms of DCIS may become invasive without treatment. This means that the cancer spreads beyond your milk ducts and into your surrounding breast tissue.
The most common treatments for DCIS are breast-conserving surgery (lumpectomy) with radiation or a mastectomy.
Breast reconstruction may be an option if you’ve had a mastectomy. Speak with your healthcare provider about your preferences for how you’d like your breasts (chest) to look after treatment.
After surgery, your healthcare provider may prescribe medications to prevent DCIS from recurring or a new type of cancer from forming in your breasts. The most common medicines are Tamoxifen (Nolvadex®) and aromatase inhibitors (such as anastrozole). This treatment is called hormone therapy. The whole treatment course lasts for five years.
Radiation and hormone therapy can cause side effects that you should discuss with your provider as you weigh treatment benefits against potential negatives.
Side effects of radiation may include:
Side effects of hormone therapy may include:
Many of the risk factors for DCIS aren’t preventable. Still, you can improve your chance of curing DCIS by catching it early. Most women and people AFAB should start receiving yearly mammograms at 40.
Talk to your provider about how often you should get a mammogram based on your risk factors.
Because DCIS is contained within a specific area of your breast and hasn’t spread, the disease can be controlled and cured with appropriate treatment. After treatment, outcomes are usually excellent. DCIS rarely recurs following treatment.
Even in those instances where DCIS does recur, the cancer isn’t life-threatening.
Expect to see your healthcare provider for a physical exam every six to 12 months for five years after treatment and then annually. You’ll also likely need to get annual mammograms.
Still, everyone’s case is different. Work with your provider to determine your care plan following treatment.
Follow your healthcare provider’s guidance so you receive check-ups and mammograms as frequently as you should. In the meantime, pay attention to your breasts so you don’t miss signs of breast cancer.
Many of these symptoms are also signs of benign (noncancerous) conditions. Get any changes checked to be sure.
A note from Cleveland Clinic
Ductal carcinoma in situ (DCIS) is one of the most treatable cancers. It doesn’t typically spread beyond your milk ducts and rarely returns after breast-conserving surgery. Talk with your healthcare provider about the benefits of your treatment options versus potential side effects or complications. Multiple factors will determine the type of surgery that’s best for you. Similarly, weigh the pros and cons of receiving additional treatments, like hormone therapy, with your provider.
Last reviewed by a Cleveland Clinic medical professional on 07/13/2022.
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