Ductal carcinoma in situ (DCIS) occurs in the breast ducts and is a pre-cancerous lesion, sometimes referred to as stage 0 breast cancer. Given that it could progress to cancer, it is recommended that a person receive treatment for it.

A person should begin treatment as soon as they receive a DCIS diagnosis. Doctors usually treat this type of breast cancer with surgery and radiation therapy.

Read on to learn more about DCIS and its treatment.

Royal poinciana resembles milk ducts for a piece about ductal carcinoma breast cancerShare on Pinterest
arthit_sr/Getty Images

DCIS starts in the milk ducts and is confined to the ducts alone, which is why it is often considered a pre-cancerous lesion. It has not spread out of the milk ducts into the fatty breast tissue.

Researchers are unsure of the exact cause of DCIS, but it could run in families. Changes in genes like BRCA1 or BRCA2 can increase the risk of DCIS.

Other general risk factors for developing cancer include:

  • Age: Cancer risk increases as a person ages.
  • Hormonal influences: Estrogen exposure over time (early menstruation, late menopause, hormone therapy) may play a role.
  • Lifestyle factors and conditions: Including diet, obesity, alcohol use, and lack of physical activity.

DCIS is often detected during a routine mammogram, as it usually doesn’t cause symptoms. Early detection and treatment help prevent progression to invasive breast cancer.

DCIS does not present with many symptoms, and doctors usually first detect it from a mammogram. Mammography screenings detect around 90% of DCIS cases. However, some people may notice a lump in their breast or nipple discharge as initial symptoms.

DCIS is rarely found during a physical exam of the breast as it rarely forms a mass. It most commonly forms calcifications in the breast.

Another way a doctor diagnoses DCIS is through a biopsy. A biopsy helps a healthcare professional identify the stage of the DCIS.

Hormone-receptor status

A pathologist may also check the biopsy for hormone receptors. The test will help to determine whether the cancer cells have receptors for estrogen and progesterone, which are types of hormones.

If the test result is positive, it means that the hormones help the cancer cells to grow. In this case, the doctor may prescribe treatments that help block the effects of estrogen or lower the levels of estrogen in the body.

Breast cancer cells may have one, both, or none of the following receptors:

  • ER-positive: This means the cells have estrogen receptors.
  • PR-positive: This means the cells have progesterone receptors.
  • Hormone receptor-positive: Healthcare professionals use this term if the cancer cells have one or both of the above hormone receptors.
  • Hormone receptor-negative: Healthcare professionals use this term if the cancer cells have neither of the above hormone receptors.

There are three grades of DCIS. They are:

  • Grade I, or low grade: This is when the DCIS cells appear similar to normal cells and grow slowly. People with low-grade DCIS have an increased chance of developing invasive breast cancer after 5 years.
  • Grade II, or moderate grade: Moderate-grade cells grow faster and appear less similar to normal cells.
  • Grade III, or high grade: At this stage, the cells grow quickly and appear different from healthy cells.

Low and moderate-grade DCIS cells have different patterns:

  • Papillary: The cells are arranged in a finger-like pattern.
  • Cribiform: There are gaps between the cells.
  • Solid: The cancer cells fill the breast duct entirely.

Healthcare professionals never recommend chemotherapy to treat DCIS.

Radiation oncologists are currently using a complex new tool called DecisionRT to guide treatment decisions in early stage breast cancer, especially DCIS.

This test examines the activity or expression of certain genes in cells, usually from a tissue sample.

DecisionRT analyzes the activity of specific genes in tumor tissue to assess how likely the cancer is to spread. This helps DecisionRT determine whether treatments like radiation or hormone therapy are necessary, allowing for more personalized care and helping some patients avoid overtreatment.

Treatment options that doctors may consider for DCIS include:

Lumpectomy (breast-conserving surgery) with radiation therapy

In this procedure, the surgeon will remove the tumor and some healthy breast tissue close by as a precaution.

Rarely, they may also remove the lymph nodes and request a biopsy to confirm that the cancer has not spread. Healthcare professionals call this a sentinel lymph node biopsy (SLNB). They are more likely to do this if the tumor is large.

After surgery a person will receive radiation therapy to destroy any remaining cells.

Lumpectomy

Sometimes, a person will only receive a lumpectomy, However, this is not standard treatment and doctors reserve this for people with a very low-grade DCIS.

A person should speak with their doctor about radiation therapy if they are unsure about this approach.

Mastectomy

If the DCIS is in many areas of the breast, or If the calcifications extent over a large area of the breast, a surgeon may remove the entire breast.

Usually, a surgeon will perform a sentinel lymph node biopsy in the setting of a mastectomy if they find invasive cancer in the mastectomy specimen.

Sometimes, a person receives reconstructive surgery immediately after the mastectomy or will have it as a separate procedure.

Depending on individual circumstances, a person would not usually receive radiation therapy after a mastectomy.

Hormonal therapy after surgery

If doctors know the cancer uses estrogen and progesterone to grow, they will likely suggest hormonal therapy.

This treatment blocks tumor receptors that bind to these hormones, or reduces the amount of estrogen and progesterone in the body. A person may continue hormonal therapy for 5 years after surgery.

COMET trial

The Comparison of Operative to Monitoring and Endocrine Therapy (COMET) trial is a clinical trial focused on people with low risk DCIS.

The trial is investigating whether watchful waiting can be a safe option for some women with low risk DCIS, rather than defaulting to surgery. It is part of a broader shift in cancer care toward personalized, less invasive treatment where possible.

DCIS is noninvasive, and some forms may never progress to invasive cancer. But current treatment often involves surgery, which may be unnecessary for some people. The COMET trial aims to reduce overtreatment and ensure women only receive intervention when it is truly needed.

The survival rate of DCIS is high because people receive their breast cancer diagnosis early and begin treatment before the cancer progresses to a more invasive type.

The vast majority of people with DCIS can expect to have a normal life expectancy. However, they are at a higher risk of developing invasive breast cancer in the future in comparison with the general population.

In instances where a person does not receive treatment for DCIS, the cancer could progress to an invasive type and spread to other parts of the body.

According to Cancer Research UK, it is rare for DCIS to return after a mastectomy. It is also rare for it to return after a lumpectomy with radiation therapy.

The researchers of a 2019 meta-analysis found the chance of developing invasive breast cancer is increased if:

  • a person is premenopausal
  • there were residual tumor cells after the treatment
  • the DCIS was previously high grade, or grade III
  • the DCIS is estrogen-negative, meaning the cancer does not have receptors for the hormone estrogen on its cells

According to a 2019 article, compared to white women, Black women are more likely to:

  • die of breast cancer after DCIS
  • develop invasive breast cancer after DCIS
  • develop ER-positive or PR-positive invasive breast cancer after DCIS

Additionally, basal-like tumors disproportionately affected Black women, and their chance of developing triple-negative breast cancer doubled after DCIS.

The researchers note that the higher mortality rates may be, in part, due to the higher chance of developing more aggressive breast cancer types, such as triple-negative breast cancer. However, it is also the result of health inequities, including a lack of access to competent oncology care and delays in treatment.

Screening for DCIS is incredibly important, as the sooner a person receives their diagnosis the earlier their treatment can start.

The Centers for Disease Control and Prevention (CDC) runs a National Breast and Cervical Early Detection Program (NBCCEDP) for people with low incomes or those who are underinsured or have no insurance.

The program also covers:

  • people whose yearly income is below 250% of the federal poverty level
  • people who are between 40 and 64 years old
  • other people who are younger or older that may need breast screening

LCIS, like DCIS, is another type of in situ high-risk lesion. A doctor would detect it through a biopsy.

Researchers are unsure if LCIS is a type of pre-cancer, as it rarely transforms into an invasive cancer. However, people with LCIS have a higher risk of developing breast cancer in the future.

Doctors tend to find LCIS after conducting a biopsy for another reason, as it does not usually show up on mammograms and is rarer than DCIS. LCIS does not require excision.

Because people with DCIS have a higher risk of developing invasive breast cancer in the future, they should remember to physically examine their breasts for lumps and speak with their doctor if they notice any changes in the breast, a lump, or discharge from the nipple.

People should be aware that mammography screenings detect most DCIS cases as the condition is often symptomless. As a result, a person should be sure to have regular screenings.

DCIS is a type of breast cancer that starts in the breast ducts.

Doctors usually catch DCIS early, which means the survival rate is high.

If a person cannot get a mammography screening due to their insurance coverage, they should look up the CDC’s NBCCEDP initiative.

After recovering from DCIS, a person should continue to self-examine their breasts and speak with a doctor if they notice any changes.