Invasive Ductal Carcinoma (IDC) Overview

The Most Common Breast Cancer

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Infiltrating ductal carcinoma (IDC), also known as infiltrating carcinoma or invasive breast cancer, is a very common type of breast cancer. It starts developing in the milk ducts of your breast, but breaks out of the duct tubes, and invades or infiltrates surrounding tissues.

Unlike ductal carcinoma in situ (DCIS), which is non-invasive cancer, IDC is not well-contained cancer. IDC has the potential to invade your lymph and blood systems, spreading cancer cells to other parts of your body. If IDC spreads beyond its original site, we say it has metastasized.

It's important to point out that the term invasive means that this cancer has spread beyond the ducts, but it's not necessarily as scary as it sounds. The term invasive doesn't mean that the cancer has spread beyond the breasts, or even that it has invaded your lymph ducts or blood vessels. While stage 0 breast cancer (carcinoma in situ) is non-invasive, all breast cancers from stage 1 to stage 4 are considered "invasive."


IDC is the most common breast cancer diagnosis and accounts for about 8 out of 10 of all invasive breast cancers. This type of breast cancer can occur at any age, but many people are over the age of 55 at the time of diagnosis. IDC is also the most common type of breast cancer in men, accounting for around 80 percent of male breast cancers.

Signs and Symptoms

Invasive ductal carcinoma can present in a number of different ways. it may feel like a hard, bumpy, irregularly-shaped lump beneath your areola or around the central area of your breast. An IDC lump will feel like it is attached to the breast tissue around it, so it may appear to be moveable. But it will be moving with the tissue that it has infiltrated.

IDC can cause nipple retraction (nipple or areola pulling in). When doing your regular breast self-exam, if your nipple won't remain standing out from your areola, it's a good idea to go see your doctor for a clinical breast exam. Dimpling of the skin, and other breast symptoms may be present as well. 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


If you find a breast lump during your breast self-exam or a clinical exam, it's best to have it properly checked out. Remember that 80 percebt of all breast lumps are not cancer. But if breast cancer is caught early, your chances of survival are very good. Some tests that are used to get a clear diagnosis of invasive ductal carcinoma are:

On a mammogram, microcalcifications can appear near an IDC mass, or a mass may be seen directly. In contrast to many benign breast conditions, breast cancer may have a spiculated appearance, meaning that rather than being round, the density extends out around a central mass like a crab. (The term cancer actually derives from the word crab due to this appearance.)

Ultrasound is helpful in distinguishing a cyst from a solid mass. Breast MRI can be very helpful, especially in younger women who have dense breast tissue that reduces the accuracy of mammography.

Even with imaging tests such as mammograms, ultrasounds, and MRI, there are a number of benign breast conditions that mimic breast cancer. A biopsy is important both to make sure a breast cancer isn't missed, but also to make sure that what appears to be a breast cancer isn't, in fact, a harmless breast condition.

Breast Cancer Doctor Discussion Guide

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

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Invasive ductal carcinoma can be diagnosed from stage 1 through 4. When an invasive breast cancer is caught and treated at an early stage, is it less likely to recur. Treatment of IDC will be tailored to the stage and other important characteristics of your tumor which are discussed below.


Doctors use the term prognosis to talk about your future outlook for survival. Your prognosis will depend on many details about your tumor, and those details will help decide which treatments will be most effective for you. Details on your pathology report will include:


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

Depending upon the stage of your cancer and other factors, further tests may be done to make sure the cancer has not spread to other regions of your body. A PET scan is a test in which radioactive sugar is injected into a vein, and then a colorful imaging test is done to look for areas in your body which appear active, as may be expected with cancer. If invasive ductal carcinoma has spread to other regions such as your lungs, your bones, your liver, or your brain it is considered metastatic breast cancer.

Follow-Up After Primary Treatments

After you've completed primary treatments for breast cancer, you will still see your oncologist for several years, for checkups. Up to 10 years, you may need to take hormone therapy if your 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.

Support and Coping

If you've been diagnosed with IDC, reach out to your family and friends. Cancer isn't a sprint, it's a marathon, and it can be very helpful to have many of your friends helping with your needs rather than just one or two. There are many emotional stages to a breast cancer diagnosis, and sometimes they all occur in a day. Take time to pamper yourself. Let go of things you can't control.

We've learned that breast cancer creates a multitude of challenges, and is a long road, but there are often silver linings along the way. In fact, studies now tell us that along with posttraumatic stress, many breast cancer survivors experience "posttraumatic" growth. In other words, having cancer really can make you a better person.

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