Ductal Carcinoma in Situ (DCIS)

What is ductal carcinoma in situ?

Ductal carcinoma in situ (DCIS) is a type of very early 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.

Healthcare providers may call DCIS noninvasive or pre-invasive breast cancer. This means that the cancer cells haven’t spread beyond the walls of your milk ducts. Ductal carcinoma in situ doesn’t typically metastasize, or spread to other organs in your body, as aggressive or invasive cancers do.

While DCIS can’t spread outside of your breast, it can turn into invasive ductal carcinoma — which can spread outside of your breast — in some cases. That’s why talking to a healthcare provider is so important. They can discuss treatment options to help reduce this risk.

How common is DCIS?

Ductal carcinoma in situ is a common form of breast cancer among women and people assigned female at birth (AFAB), accounting for 20% to 25% of new breast cancer diagnoses each year. Men and people assigned male at birth (AMAB) can get DCIS, but it’s rare (less than 0.1% of cancer diagnoses).

DCIS cases are on the rise. But experts believe this is because more people are being diagnosed and treated, not because more people are getting DCIS.

What are the symptoms of ductal carcinoma in situ (DCIS)?

Ductal carcinoma in situ doesn’t generally cause symptoms. But a few people with DCIS may notice a breast lump, itchy skin or nipple discharge (like blood).

What causes ductal carcinoma in situ?

DCIS happens when healthy cells in your milk duct mutate (change) and grow uncontrollably. But experts aren’t sure why these changes take place to begin with, or why DCIS spreads in some cases but not others.

Risk factors for DCIS

Certain factors can increase your risk of ductal carcinoma in situ, like:

• A biological family history of breast cancer.
• A personal history of breast cancer or atypical hyperplasia.
• Being assigned female at birth (AFAB).
• Being over age 30.
• Getting your period before age 12.
• Having a baby after 30.
• Having dense breast tissue.
• Having gene mutations associated with increased cancer risk (BRCA 1 and BRCA 2).
• Having previous radiation therapy directed at your breasts or chest.
• Never being pregnant or breastfeeding.
• Starting menopause after age 55.

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 ductal carcinoma in situ don’t have family members with breast cancer. Risk factors are all about probability — what may increase your chance of developing a condition.

What are the complications of ductal carcinoma in situ?

Ductal carcinoma in situ can turn into invasive ductal carcinoma if you don’t treat it. If you have DCIS, it’s important to get treatment as soon as possible.

If you’ve received treatment for DCIS, you have a higher risk of developing other health conditions as you age. This includes osteoporosis, high blood pressure and heart disease. To reduce your risk of these complications, ask your healthcare provider how often you should have screenings and follow-ups.

How is ductal carcinoma in situ diagnosed?

Healthcare providers detect over 90% of DCIS cases during mammograms. If you receive suspicious mammogram results, they’ll do a biopsy.

• Mammogram. In addition to a routine screening mammogram, your healthcare provider might order a diagnostic mammogram. This test provides more detailed views of your breast tissue. It takes longer than a screening mammogram.
• Breast biopsy. Healthcare providers use this test to confirm that cancer cells are in your breast (s).

Grades of DCIS

Healthcare providers categorize DCIS into three grades:

1. Low (slow-growing). The cancer cells look a lot like healthy breast cells.
2. Intermediate (fast-growing). The abnormal cells sort of look like healthy breast cells.
3. High (growing uncontrollably). The cancer cells look completely different from healthy breast cells.

Stages of DCIS

Ductal carcinoma in situ is a highly treatable and curable stage 0 breast cancer. Healthcare providers classify cancer into stages from 0 to IV (4). Although DCIS is always stage 0, the tumor can be any size and may be located within several milk ducts inside of your breast.

How is ductal carcinoma in situ treated?

Although DCIS isn’t an aggressive cancer, it’s still important to get treatment or have a healthcare provider monitor your condition closely. Some forms of ductal carcinoma in situ 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-conserving surgery (BCS) or lumpectomy removes all cancer cells, along with healthy breast tissue bordering the cancer growth. Removing small amounts of nearby healthy tissue increases the chance that no abnormal cells are left behind. Your provider will leave most of your breast intact.
• Radiation therapy typically follows BCS. Some people need this therapy for a few days, others for a few weeks. Your healthcare provider can tell you about your personalized treatment plan.
• Mastectomy removes the entire affected breast or both breasts (double mastectomy). You may need a mastectomy if you’re not a candidate for BCS. Mastectomy may be a better option if the cancer has spread throughout multiple milk ducts or if a tumor is especially large.

Breast reconstruction may be an option if you’ve had a mastectomy. If you have BCS, you likely won’t need breast reconstruction. Speak with your healthcare provider about your preferences for how you’d like your breasts (chest) to look after treatment.

What happens after DCIS surgery?

After surgery, your healthcare provider may prescribe medications to prevent DCIS from recurring (coming back). The most common medicines are tamoxifen (Nolvadex^®) and aromatase inhibitors (like anastrozole). This treatment is called hormone therapy. The whole treatment course lasts for five years.

Can ductal carcinoma in situ be prevented?

Many of the risk factors for DCIS aren’t preventable. Still, you can improve your chance of curing DCIS by catching it early. Most people assigned female at birth should start receiving yearly mammograms at age 40.

Talk to your provider about how often you should get a mammogram based on your risk factors.

What’s the life expectancy for people with DCIS?

DCIS survival rates are excellent. According to the American Cancer Society, nearly all people with ductal carcinoma in situ can be cured with treatment.

After treatment, outcomes are usually excellent. Ductal carcinoma in situ rarely recurs (returns). Even in those instances where DCIS does recur, the cancer isn’t life-threatening.

How do I take care of myself?

With DCIS, 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.

When should I see my healthcare provider?

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.

What questions should I ask my doctor?

If you have DCIS, here are some questions you may want to ask your healthcare provider:

• What type of treatment do I need?
• How long will treatment take?
• Will I be able to work while having treatment?
• How often will I need follow-ups?
• How often will I need mammograms?