Ductal breast cancer begins in your milk ducts. It includes invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS).

Ductal breast cancer is the most common type of breast cancer, and breast cancer is the most common form of cancer in the United States.

Approximately 297,790 people in the United States will receive a breast cancer diagnosis in 2023. Based on data from 2017 to 2019, about 13% of women will be diagnosed with female breast cancer during their lifetime.

Although breast cancer typically affects cisgender women and others assigned female at birth, it’s also possible for people assigned male at birth to develop breast cancer.

Ductal breast cancer makes up most cases of male breast cancer, according to the Centers for Disease Control (CDC).

You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “male” and “female” or “men” and “women.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

There are two main types:

  • Invasive ductal carcinoma (IDC): This type of cancer makes up about 70–80% of all breast cancer diagnoses. It begins in the milk ducts and spreads to the surrounding tissues.
  • Ductal carcinoma in situ (DCIS): DCIS is considered an early stage of cancer, noninvasive cancer, or pre-cancer, as it hasn’t yet started to spread into the rest of the breast tissue. DCIS may eventually lead to IDC.

Symptoms may include:

It’s important to note that most people with ductal breast cancer don’t experience any symptoms. This is especially true for DCIS. Regular breast cancer screenings can help detect ductal breast cancer in its early stages.

Most breast symptoms or changes aren’t caused by cancer. But if you do notice any unusual symptoms, it’s best to make an appointment with a healthcare professional to check for abnormal cells.

As with other forms of cancer, it’s not entirely clear why some people develop ductal breast cancer, and some don’t.

However, experts have identified that certain groups of people are more likely to develop breast cancer than others.

Risk factors for ductal breast cancer include:

  • Age: As you get older, your risk of developing breast cancer increases.
  • Alcohol use: Frequent drinking or alcohol use disorder raises your risk.
  • Certain reproductive factors: People are more likely to develop breast cancer if they began menstruating before the age of 12, started menopause after 55, have never carried a pregnancy to term, or gave birth at an older age.
  • Dense breast tissue: Some people naturally have dense breast tissue. This can increase your risk of breast cancer and make mammograms harder to read.
  • Family history of breast cancer: You may be more likely to develop breast cancer if a close female relative has had it. However, most people who develop it have no family history of the disease.
  • Genes: If you have certain gene mutations, such as BRCA1 and BRCA2, you’re more likely to develop breast cancer than people who don’t.
  • History of breast cancer: If you’ve had breast cancer before, you may develop it again — possibly in your other breast or a different area of your breast.
  • Hormone therapy: Postmenopausal estrogen and progesterone medications may increase your risk of breast cancer. Transgender women may be more likely to develop breast cancer than cisgender men, possibly due to hormone treatment.
  • Smoking tobacco: There’s a link between smoking tobacco and breast cancer. Exposure to secondhand smoke may also increase your risk.

If you think you may be at risk for developing breast cancer, speak with a healthcare professional. They can advise you on how often you should get a mammogram as well as lifestyle changes you can make to help reduce your overall risk.

A healthcare professional will typically perform several tests to identify and diagnose ductal breast cancer.

This includes:

  • Physical exam: Your doctor will manually examine your breast for lumps or thickening.
  • Mammogram: A mammogram is an X-ray of your breast that can detect cancer.
  • Biopsy: Your doctor will send a sample of your breast tissue to a lab to be examined. A breast biopsy can help determine if a lump in your breast is cancerous or benign.
  • Ultrasound: A breast ultrasound uses sound waves to provide a detailed view of breast tissue and blood flow. It doesn’t use radiation and is safe for people who are pregnant.
  • Magnetic resonance imaging (MRI): MRIs can detect small breast lesions. Doctors use breast MRIs to screen people with a high risk of developing breast cancer.

The next step is to determine the stage of the cancer:

  • Stage 0: There are abnormal cells in your ducts, but they aren’t spreading yet. DCIS is considered stage 0.
  • Stage 1: The cancer is only in your breast, with a tumor 2 centimeters (cm) or 0.75 inches (in) or less in diameter.
  • Stage 2: The cancer has spread to nearby lymph nodes, or the tumor is 2–5 cm (0.75–2 in) in diameter.
  • Stage 3: The cancer has spread extensively in your breast, surrounding tissues, and lymph nodes, but no further.
  • Stage 4: The cancer has metastasized, meaning it’s spread to more distant sites in your body.

If a healthcare professional has diagnosed you with DCIS, they may grade it. This grading system is used to rate the likelihood of your DCIS returning after treatment:

  • High-grade, nuclear grade 3, or high mitotic rate: DCIS has a higher likelihood of developing again after treatment.
  • Intermediate-grade, nuclear grade 2, or intermediate mitotic rate: DCIS is less likely to return after treatment.
  • Low-grade, nuclear grade 1, or low mitotic rate: This grade of DCIS is the least likely to return after treatment.

An oncologist, a doctor who specializes in cancer, will recommend a treatment plan based on:

  • the type of cancer you have
  • the stage and grade of the cancer
  • your specific health needs

Ductal breast cancer treatments include:

  • Surgery: This can include a lumpectomy, which preserves as much of your breast as possible while removing the abnormal cells and surrounding tissues, or a mastectomy, which removes as much breast tissue as possible.
  • Radiation therapy: This therapy uses high energy beams to damage the DNA of abnormal and cancerous cells.
  • Hormonal therapy: Your clinician might prescribe hormonal therapies if cancer cells are growing in response to estrogen and progesterone.
  • Chemotherapy: You usually wouldn’t need chemotherapy for DCIS, but it’s often used for IDC after a lumpectomy or mastectomy. It can reduce the likelihood of cancer spreading.
  • Targeted therapy: This treatment blocks the spread of molecular targets associated with cancer.
  • Immunotherapy: This therapy triggers your immune system to destroy cancer cells.

Your outlook depends on many factors, including the stage of diagnosis.

The 5-year relative survival rate for breast cancer is about 90.8%. This is an average across all breast cancer subtypes and stages.

Localized breast cancer (that is, the cancer hasn’t spread beyond the breast tissue) has a 99.3% 5-year relative survival rate. The rate drops to 86.3% for regionalized breast cancer and 31% for breast cancer that has spread to distant parts of the body.

DCIS, which is stage 0 ductal breast cancer, has a 100% 5-year survival rate. A 2015 study, which looked at 100,000 women over 20 years, found that only 3.3% percent of women treated for DCIS later died from breast cancer.

The survival rate for breast cancer has steadily increased over time, partly because of newer and more effective treatments.

Sian Ferguson is a freelance health and cannabis writer based in Cape Town, South Africa. She’s passionate about empowering readers to take care of their mental and physical health through science-based, empathetically delivered information.