Understanding DCIS: Early Stage Breast Cancer

Ductal carcinoma in situ (DCIS) is a very early form of breast cancer that makes up about 1 out 5 cases of breast cancer.

While any cancer diagnosis is scary, DCIS is noninvasive and very treatable. With appropriate treatment and follow-up care, the outlook is excellent. And the five-year survival rate for people diagnosed with DCIS is 98%.

What is DCIS?

DCIS is the earliest stage of breast cancer, sometimes called stage 0 breast cancer.

The name ductal carcinoma in situ is a bit confusing. Here’s what it means:

• Ductal: The cancer is in the cells lining the milk ducts. It might be in one or both breasts.
• Carcinoma: These ductal cells become abnormal (cancerous).
• In situ: The cancer stays “on site” where it started. It might spread to more ductal cells, but it does not spread to other areas.

DCIS is noninvasive, meaning it has not spread from where it started, but it still needs to be treated. Although DCIS itself has a great prognosis, research does show that people diagnosed with DCIS have a higher risk of developing invasive cancer later. Anywhere from 20 to 50% of DCIS cases might be a precursor to a higher stage of breast cancer.

Healthcare providers can’t tell which cases will progress. So the safest approach is to treat all cases of DCIS quickly. Treating DCIS intensively leads to better outcomes and lowers the risk of invasive cancer down the road.

Symptoms and diagnosis of DCIS

DCIS usually doesn’t cause any noticeable symptoms. Some people might notice a lump in their breast, skin irritation or itchiness, a sore or discharge from the nipple. But this isn’t common. Most of the time, DCIS is caught by a mammogram — those regular screenings are important!

If you have DCIS, the mammogram might show microcalcification clusters. These clusters are calcium deposits in the breast. They might be there for many reasons. In fact, they’re pretty common in women over 50. However, certain patterns of microcalcifications can indicate an early stage of cancer. So, if these are spotted on your mammogram, you’ll need more imaging done.

If you have signs of DCIS, your healthcare provider (HCP) may request one or more of the following:

• Diagnostic mammogram: Provides more detailed X-ray images of the breast than a screening mammogram, often from different angles or positions.
• Ultrasound: Uses sound waves to get images of the breast tissue. Sometimes an ultrasound is used to guide a biopsy.
• Breast MRI: Magnetic resonance imaging is more sensitive than a mammogram or an ultrasound.

After imaging, the next step is a biopsy: a small piece of tissue is taken from the breast, then analyzed by a pathologist. The analysis determines what kind of DCIS is present and the best course of treatment.

Different types of DCIS

DCIS is categorized by something called nuclear grade. This scale “grades” or compares how the cancer cells look in comparison with normal breast cells. The cells might be low, intermediate, or high grade. A higher grade means the cancer cells are more abnormal and fast-growing.

It’s also important to determine the hormonal makeup of the cancerous cells. This helps doctors decide on the best treatment approach. Some cancer cells have hormone receptors for estrogen or progesterone, or both. Having these receptors is favorable. It means the cancer grows more slowly and depends on hormones to survive. Most cases of DCIS are hormone-receptor positive.

How is DCIS treated?

Treatment for DCIS is usually straightforward: surgery, often followed by radiation therapy. The radiation ensures that all cancerous cells are removed. In some cases, hormone therapy may be recommended. Chemotherapy is not used to treat DCIS.

Surgery

A lumpectomy is also called a partial mastectomy or breast-saving surgery. The surgeon removes tissue from the breast. The tissue includes the cancerous cells and some healthy tissue around the area. The breast itself is not removed.

A mastectomy is a surgery that removes all tissue, or the entire breast. Patients might opt to have breast reconstruction surgery after a mastectomy.

Which surgery is needed depends on the DCIS spread. If the cancer is in a small, contained area, a lumpectomy is usually possible. If the cancer hasis spread out or scattered through the ductal cells, a mastectomy will be needed.

Radiation therapy

Radiation therapy uses high-energy beams, usually X-rays, to kill cancer cells that were not removed during surgery. It’s associated with a lower risk of recurrence.

Hormone therapy

If the cancer cells have hormone receptors, your healthcare provider might recommend hormone therapy to help prevent recurrence. If you have a mastectomy, hormone therapy is usually not needed.

Does DCIS recur?

While DCIS can come back, its recurrence rate is low. For people who have a lumpectomy followed by radiation therapy, it’s less than 15%.

The DCIS grade also has an effect on the recurrence rate. A lower grade equals a lower risk of recurrence. However, the risk of recurrence is higher for Black women than for Asian, Hispanic, or white women. That may be because white women benefit from more follow-up imaging surveillance. These systemic racial/ethnic disparities have fatal consequences: the rate of breast cancer mortality after DCIS is higher for Black women.

Read: Why Do Women of Color Have Worst Breast Cancer Outcomes? >>

Regular mammograms help catch DCIS so it can be treated quickly. After treatment for DCIS is complete, regular screenings help spot any abnormalities. With good follow-up, you’ve got everything on your side to stay healthy after a DCIS diagnosis.

This educational resource was created with support from Merck.