What is ductal carcinoma in situ?

Ductal carcinoma in situ (DCIS) is also sometimes called stage 0 breast cancer. This is because it is very localized and hasn’t spread to any of the surrounding breast tissue. The word “ductal” refers to the location — the milk ducts. “Carcinoma” is cancer that's in the cells of the outer tissue layer of any organ. “In situ” means that it’s in its original location and hasn't spread yet.

Because DCIS is a very early form of breast cancer, it’s also very treatable. Detecting the disease and treating it is important to prevent it from spreading or becoming an invasive form of breast cancer. When it's left untreated, between 40% and 50% of people with DCIS develop invasive breast cancer, as the Susan G. Komen Foundation reports.

Common related conditions
Breast Cancer Invasive Ductal Carcinoma (IDC)

Causes of ductal carcinoma in situ

Doctors don’t know exactly what causes DCIS, what they do know is how it starts. Cells within the lining of the milk ducts go through changes. Then, they start growing out of control.

Risk factors of ductal carcinoma in situ

Even though doctors don't know why it happens, they do think that there's a link to your genes and other factors.

Risk factors associated with DCIS include:

  • Age —older people are more likely to develop ductal carcinoma in situ
  • Family history — having close family members who have had breast cancer
  • Personal history — if you’ve had benign breast disease, you’re more at risk for DCIS
  • Hormone replacement — taking estrogen-progesterone combination therapies for three years or longer after menopause puts you at higher risk of ductal carcinoma in situ
  • Genetics — having the BRCA1 or BRCA2, two genes that scientists call "breast cancer genes"
  • Being overweight or obese
  • Race — Caucasians and African-Americans have a higher risk for ductal carcinoma in situ

Symptoms of ductal carcinoma in situ

Most people don’t have any symptoms with DCIS. That’s one of the reasons that getting regular breast cancer screenings is so important.

Some patients notice things like:

  • A lump in your breast, but this is not common
  • Nipple discharge that's bloody

Diagnosis of ductal carcinoma in situ

Unlike other types of breast cancer, patients rarely have a noticeable lump, although they might. Often, doctors find the disease on a mammogram, where it looks like a shadow. If your doctor thinks you might have DCIS, a test called a biopsy might be needed.

During a biopsy, your doctor will use a needle to take a sample of the tissue from inside your breast. Doctors can look at it under a microscope to see if there's evidence of cancer. Your doctor might also order imaging tests like MRI or ultrasounds to get a better look at the tumor. Imaging also lets a doctor see if it has spread.

Treatments for ductal carcinoma in situ

The right treatment for you depends on how fast the cancer grows, the tumor’s size and a few other factors. Patients and doctors work together to come up with the right plan.

Often, patients can choose between several options:

  • Breast-conserving surgery removes the tumor and some of the healthy tissue around it. Most patients also get radiation therapy to lower the chances of the cancer coming back.
  • Mastectomy removes the whole breast. This might be a better option if there's a couple spots with DCIS or if breast-conserving surgery wouldn't take the cancer out completely.
  • Hormone therapy might be used after either type of surgery depending on the type of tumor the patient has.

Recovery from ductal carcinoma in situ

DCIS is highly treatable. The 20-year survival rate for DCIS patients is around 97%.

After treatment, you can expect follow-up examinations with your doctor.

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