If you’ve recently undergone screening for breast cancer and been diagnosed with comedocarcinoma, you may have questions about this early stage breast cancer, such as its potential severity and how it’s treated.

After a comedocarcinoma diagnosis, your next step should be a discussion with your doctor.

In this article, we’ll provide information that can help inform that discussion. We’ll take a look at how comedocarcinoma is graded (its risk for recurrence), along with symptoms, treatments, and outlook.

Comedocarcinoma is a type of breast cancer that’s considered very early stage (stage 0) or precancerous, according to the National Cancer Institute (NCI). It’s also a subtype of ductal carcinoma in situ (DCIS), which accounts for nearly 1 in 5 new breast cancer diagnoses, according to the American Cancer Society (ACS).

DCIS is considered a noninvasive breast cancer because it only affects cells in the milk ducts and has not spread to nearby tissues. However, nearly all cases of DCIS are treated to ensure the cancer doesn’t spread (metastasize) in the future.

Unlike other forms of breast cancer, comedocarcinoma consists of small plug-like growths that you may not realize you have until you undergo a regular breast screening. This precancer does not always cause symptoms, which makes routine mammography even more important in early detection.

While there are no known causes for comedocarcinoma, the following risk factors could increase your chances of developing DCIS:

According to one 2020 study, risk factors for estrogen receptor-positive DCIS in African American women include:

  • first-degree family history of DCIS
  • early menstruation
  • using birth control pills in the last 10 years
  • having a first birth later in life

Comedocarcinoma is considered a “high-grade” subtype of DCIS that contains dead cancer cells inside the lesions.

DCIS may be rated grades I to III, as follows:

  • Grade I: This indicates a low risk of recurrence and means that the cancerous cells look similar to healthy ones under a microscope
  • Grade II: Also called moderate grade, this means that the cancerous cells may grow faster and there’s a higher chance of recurrence.
  • Grade III: This is also known as “high-grade” DCIS and means there’s a good chance that the cancer will return.

This means that while comedocarcinoma is considered a precancer, it’s also the highest grade — and potentially the most aggressive — form of DCIS.

Comedocarcinoma doesn’t always cause symptoms, but it’s possible to experience breast pain. In some cases, this type of breast cancer may also cause nipple discharge, which, unlike other types of breast cancer, is usually clear instead of bloody.

DCIS may also possibly cause breast lumps. This is unlike more invasive breast cancers, per the ACS, which may cause:

  • breast swelling
  • dimpled skin that may resemble an orange peel
  • flaky, red, or thickened nipples and/or breast skin
  • nipples that turn inward
  • swollen lymph nodes under your arms or collarbone

You should see a doctor right away if you experience any changes or discomfort in the breast area. The same guidance applies even if you’ve already been diagnosed with stage 0 breast cancer or a benign (noncancerous) breast condition.

Comedocarcinoma is most often found during a routine mammogram. In fact, it’s estimated that 70% to 90% of DCIS cases are detected as abnormal calcifications during this breast imaging method. These may appear as small white spots on a mammogram.

In addition to mammography, according to Breastcancer.org, a doctor may also confirm the presence of comedocarcinoma with a combination of:

Different types of DCIS, including comedocarcinoma, are confirmed via a biopsy sample under a microscope. “Comedo” describes what the cancer looks like.

Once comedocarcinoma is confirmed, a pathologist determines staging. The stage of a cancer describes how much cancer there is and how far it has spread. Staging helps doctors determine treatment and outlook.

Camedocarcinoma, like other DCIS types, are almost always stage 0 because the cancer has not spread beyond where it started.

While comedocarcinoma is considered a precancer, like other types of DCIS, it has the potential to become an invasive cancer if left untreated, according to the ACS.

For this reason, DCIS is treated with either a mastectomy or breast-conserving surgery to remove cancerous cells. Either surgical method may be followed up with radiation therapy.

In cases where DCIS is hormone-receptor positive, a doctor may also recommend taking hormone therapies, such as aromatase inhibitors or an estrogen modulator called tamoxifen, according to the ACS.

The extent of treatment for DCIS depends on its grading. Since comedocarcinoma is considered a grade III cancer, a doctor may recommend a combination of treatments.

Like other types of DCIS, comedocarcinoma is considered stage 0, which is the lowest rating on cancer staging scales.

However, it’s still possible for DCIS to spread outside of the ducts into nearby tissues. In such cases, the cancer may become invasive and spread to other areas of the body. Most cases of DCIS are treated to prevent this from happening.

According to data reported by the NCI, DCIS carries a low risk of death, even decades later. The risk of death was found to be higher in African American women and women diagnosed before age 35.

Comedocarcinoma is a subtype of DCIS, which is a noninvasive or early form of breast cancer. These growths don’t usually cause symptoms, and they’re most often found during regular breast cancer screenings, such as mammography.

While the overall risk of death is low with this type of cancer, it’s possible for comedocarcinoma to spread outside of the breast ducts and invade other tissues. Because of this, a doctor will likely recommend preventive treatments such as surgery or hormonal therapies.