An Overview Invasive Ductal Carcinoma (IDC)

A.K.A. infiltrating carcinoma or invasive breast cancer

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Infiltrating ductal carcinoma (IDC), also known as infiltrating carcinoma or invasive breast cancer, is the most common type of breast cancer. It starts developing in the milk ducts of your breast, and may break out of the ducts and invade surrounding tissues.

What to Know About Invasive Ductal Carcinoma (IDC)

Lara Antal / Verywell

The term "invasive" means the cancer has spread beyond the ducts. But this doesn't mean IDC has spread beyond the breasts, or even that it has invaded the lymph nodes or blood vessels. And while stage 0 breast cancer (carcinoma in situ) is non-invasive, all breast cancers from stages 1 to 4 are considered "invasive."


IDC accounts for about 8 out of 10 of all invasive breast cancers, according to the American Cancer Society. This type of breast cancer can occur at any age, but many people are over the age of 55 at the time of diagnosis.

It affects both women and men, accounting for around 80% of male breast cancers.

Signs and Symptoms

Performing a breast self-examination (BSE) monthly, in addition to getting any recommended routine screening, is the best way to keep an eye on breast health. Knowing what is normal for you and what changes in the breast feel like is critical to recognizing early signs of breast cancer.

Signs of breast cancer (in general) that may be found during a breast self-examination may include:

  • Swelling in all or part of the breast
  • Skin irritation
  • Dimpling (having the texture of an orange peel)
  • Breast and/or nipple pain
  • Nipple retraction
  • Red, scaly and/or thick skin in the breast and/or nipple
  • Nipple discharge, other than milk
  • Lump in the underarm 

Invasive ductal carcinoma, in specific, can present in a number of different ways. Particular presentations worth noting:

  • A hard, bumpy, irregularly-shaped lump beneath the areola or around the central area of the breast
  • A lump that feels attached to the breast tissue around it and may seem movable (it is, but will be moving with the tissue that it has infiltrated)

Most of the time breast pain is due to a benign breast condition, but, in contrast to what many women (and men) hear, pain can sometimes be a symptom of breast cancer. Therefore, it is a good idea to report breast pain to your healthcare provider in order to determine the cause.


The underlying causes of IDC are not fully known. Researchers think certain hormonal, environmental, and lifestyle factors—including smoking, poor diet, and prior radiation to the chest—increase a person’s risk for breast cancer. That said, many people develop breast cancer without such known risk factors.

In some cases, IDC is traced to certain attributes including:

  • Breast cancer gene 1 (BRCA1) or breast cancer gene 2 (BRCA2), two tumor suppressor genes that are inherited.
  • ErbB2 gene. 20% to 25% of breast cancers are HER2 positive, which means the gene is amplified (i.e., there are too many copies of the gene therefore too much of the protein being produced), which produces human epidermal growth factor receptor 2 (HER2), protein receptor that promotes cancer cell growth. This is not inherited.


If you find a breast lump during your breast self-exam or a clinical exam, it's best to have it properly checked out. Fortunately, 80% of all breast lumps are not cancer and are instead related to benign (non-cancerous) issues that may mimic the disease. For the other 20%, if breast cancer is caught early, your chances of survival are generally very good.

Some tests that are used to get a clear diagnosis of invasive ductal carcinoma include:

  • Mammogram: Mammography uses X-rays to create images of the breast. Like other types of X-rays, mammograms show shades of black, gray, and white, depending on breast tissue density. Normal fat tissue appears dark gray. Tissue affected by breast cancer or benign breast conditions is denser and appears lighter gray and white. As such, IDC may appear as a white mass on a mammogram. However, the tumor cells, at times, don't stay within the borders of the mass and invade nearby breast issue, appearing fuzzy looking on imaging.
  • High-resolution ultrasound: Ultrasound imaging of the breast can help to detect benign breast conditions and breast cancer. An ultrasound is usually done after a mammogram shows something abnormal or unusual looking. Ultrasound is helpful because images can be viewed from any direction. IDC appears as an indistinct, spiculated (having surface "spikes") mass.
  • Breast MRI: Magnetic resonance imaging (MRI) uses magnetic images and radio waves to take images of breast tissue. Your healthcare provider may request an MRI to get more information about a breast mass or abnormality. Breast MRIs can be very helpful, especially in younger women who have dense breast tissue, which may decrease the accuracy of mammography.
  • Breast biopsy: Your healthcare provider will ask for a biopsy if something suspicious is seen on a mammogram or other imaging. It involves obtaining a small part of the growth for examination under a microscope. A biopsy is important to confirm whether a suspicious area is cancerous or benign.

Breast Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman


The goal of treating any breast cancer is to get rid of the cancer cells and to prevent recurrence. Treatments for IDC may include:

  • Surgery: A lumpectomy involves the removal of the cancer and a small area of healthy tissue around it. A mastectomy removes the entire breast. 
  • Chemotherapy: Chemotherapy drugs may be used before surgery to shrink the tumor and make the cancer operable. It may also be given after surgery to prevent cancer cells from returning.
  • Radiation: Radiation treatments are given after surgery and chemotherapy to prevent cancer cells from returning.
  • Hormone therapy: Certain medicines may be given if the cancer cells have specific hormone receptors.
  • Targeted therapy: HER2 cancer cells are treated with targeted therapy drugs, such as Herceptin (trastuzumab).

The goal of treatment is to give you the best possible outcome, and your healthcare provider may decide to use a combination of therapies to get you there.  

Considering Clinical Trials

Clinical trials use new, yet-to-be-approved drugs to see if they work and how they safe they are. This may be a way for you to try a treatment that isn’t available to everyone, and your healthcare provider can be a great source of information about which trial might work for your unique situation. 


After you've completed primary treatments for breast cancer, you will still see your oncologist for several years for check-ups. You may need to take hormone therapy for up to 10 years if the tumor was estrogen- or progesterone-sensitive.

You will continue to have mammograms on any breast tissue that you still have, as well as bone density scans if you are menopausal to make sure you don't develop osteoporosis.


Healthcare providers use the term prognosis to talk about your future outlook and survival. Different things influence a person’s prognosis with IDC, including:

  • Whether IDC is a new diagnosis or a recurrence
  • The stage of the cancer and whether it is confined to the breast or has spread to lymph nodes, other tissue, or organs
  • Hormone-receptor status and HER2 status
  • Treatment responses
  • Your age, overall health, and menopausal status (if female)

A Word From Verywell

If you've been diagnosed with IDC, the support you may need can come in many forms. Whether it is a close friend to vent to, a support group or therapist, or family members who offer practical help such as housework, childcare, or getting you to appointments, know the reaching out and getting the care, love, and understanding you need is also an important part of your treatment process. For your part, do what you can to take care of yourself: Eat healthy, keep moving, pamper yourself, and let go of things you can't control as best you can.

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10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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