Invasive Ductal Breast Carcinoma

ductal carcinoma, infiltrating ductal carcinoma, IDC breast cancer, invasive ductal breast cancer

Invasive ductal carcinoma is the most common type of breast cancer, accounting for about 80% of all cases. It starts in the milk ducts of the breast and can spread to surrounding tissue and other parts of the body. Early detection through mammography often allows doctors to treat it successfully before it spreads.

Table of contents

• What is invasive ductal carcinoma?
• Who gets invasive ductal carcinoma?
• Signs and symptoms
• Causes and risk factors
• How is it diagnosed?
• Stages of the disease
• Cancer grades
• Types of invasive ductal carcinoma
• Treatment options
• Possible complications

What is invasive ductal carcinoma?

Invasive ductal carcinoma starts in cells that line the milk ducts in your breast (the tubes that carry milk from the milk-producing areas to the nipple). The word “invasive” means the cancer has spread from where it started. In this case, abnormal cells break through the walls of the milk ducts and spread into the surrounding breast tissue.^[1]

From the breast tissue, the cancer can enter your bloodstream or lymphatic system (a network of vessels that helps fight infection and remove waste from your body). Once in these systems, it can travel to other parts of your body.^[1]

Invasive ductal carcinoma is different from a condition called ductal carcinoma in situ (DCIS). With DCIS, the abnormal cells are all contained inside the milk ducts and have not broken through the duct walls. DCIS is considered the earliest stage of breast cancer and is non-invasive.^[7]

• Breast milk ducts
• Breast tissue
• Lymphatic system
• Bloodstream

Who gets invasive ductal carcinoma?

Invasive ductal carcinoma accounts for about 80% of all breast cancer cases in women. It typically affects women age 55 and older, though it can occur at any age.^[1][5]

While breast cancer is much more common in women, it can also occur in men. About 98 percent of male breast cancers are invasive ductal carcinoma, making it the most common type of breast cancer in men as well.^[3]

In 2025, an estimated 319,750 new cases of invasive breast cancer will be diagnosed in the United States.^[3]

Signs and symptoms

In many cases, routine mammograms (special X-rays of the breast) detect invasive ductal carcinoma before you have noticeable symptoms. This is one reason why regular screening is so important.^[1][5]

When symptoms do appear, they may include:^[1][5]

• A lump or mass in your breast, which may feel as small as a pea
• A lump or thickening in or near your breast or in your underarm that lasts through your menstrual cycle
• A change in the size, shape, or contour of your breast
• Swelling of all or part of the breast
• Changes in the look or feel of your skin on your breast or nipple, such as dimpling, puckering, scaling, or redness
• Skin that looks like an orange peel
• A marble-like hardened area under your skin
• Your nipple turning inward
• Discharge from your nipple that is blood-stained or clear (not breast milk)
• Breast or nipple pain
• Skin irritation
• A lump or swelling in the underarm area

Causes and risk factors

Experts don’t know the exact cause of invasive ductal carcinoma. However, several factors may increase your risk of developing this condition:^[1]

• Smoking
• Consuming beverages containing alcohol
• Having obesity
• Having had radiation therapy to your chest area
• Starting your menstrual cycle earlier or later than usual
• Having children later in life

Certain inherited genetic mutations may also increase your risk. An inherited genetic mutation is an abnormal gene or genes that you inherit from your biological parents. These mutations include changes in genes called BRCA1 and BRCA2.^[1]

It’s important to know that most people who develop breast cancer do not have any known risk factors. This means that even without these risk factors, it’s still important to be aware of breast health and get regular screenings.^[11]

How is it diagnosed?

If your doctor suspects invasive ductal carcinoma, they will start with a physical examination. They’ll check for lumps in your breasts and may also check for swollen lymph nodes in your armpit (small organs that are part of your immune system).^[1]

Diagnosing invasive ductal carcinoma involves a combination of tests and almost always includes:^[5]

• A breast physical exam
• A mammogram
• A biopsy (removing a small sample of tissue to examine under a microscope)

Other tests that may be used include:^[1][5]

• Breast ultrasound (using sound waves to create pictures of the inside of the breast)
• Breast MRI (magnetic resonance imaging, which uses magnets and radio waves to create detailed pictures)

During a biopsy, a doctor uses a needle to take a sample of the abnormal tissue. A specialist called a pathologist examines the tissue sample under a microscope to determine if cancer is present.^[10]

Stages of the disease

The stage of invasive ductal carcinoma describes how far the cancer has spread. Healthcare providers determine the stage based on factors like the tumor’s location and size. Knowing the stage helps you and your doctor decide on the best treatment options and understand what to expect.^[1][5]

Generally, the stage of invasive ductal carcinoma is described as a number on a scale from I to IV:^[5]

• Stage I, II, and III describe early-stage cancers that have not spread outside the breast or the lymph nodes in the underarm on the same side as the breast cancer
• Stage IV describes cancers that have spread outside the breast and underarm lymph nodes to other parts of the body, such as the bones or liver

There is also Stage 0, which refers to cancer that is localized and has not yet become invasive.^[1]

Cancer grades

The cancer grade is different from the cancer stage. While the stage tells you how far the cancer has spread, the grade describes how the cancer cells look under a microscope. The grade is based on how much the cancer cells look like normal cells.^[5]

There are three cancer grades:^[5]

• Grade 1 (low grade): The cancer cells look more like normal cells and usually grow slowly. They are less likely to spread.
• Grade 2 (moderate grade): The cancer cells are growing faster than grade 1 but slower than grade 3.
• Grade 3 (high grade): The cancer cells look very different from normal cells and are growing faster than grade 1 and grade 2. They are more likely to spread.

Types of invasive ductal carcinoma

Doctors classify invasive ductal carcinoma into different types based on the tumor’s hormone receptor status. Receptors are protein molecules on the surface of cells. They can attract or attach to certain substances in your blood, including hormones like estrogen and progesterone. Some breast cancers need these hormones to grow.^[1]

Knowing a tumor’s hormone receptor status helps doctors decide which treatment will be most effective. Common types of invasive ductal carcinoma include:^[1]

• ER-positive (ER+) breast cancer: Cancer cells have receptors for estrogen
• PR-positive (PR+) breast cancer: Cancer cells have receptors for progesterone
• HER2-positive (HER2+) breast cancer: Cancer cells have high levels of a protein called HER2
• Triple-negative breast cancer: Cancer cells don’t have receptors for estrogen, progesterone, or HER2

Treatment options

Treatment for invasive ductal carcinoma depends on many factors, including the type of cells the cancer started in, the size of the cancer, whether it has spread, how abnormal the cells look, whether the cells have receptors for particular drugs, your general health, and whether you have had menopause.^[6]

Treatment options may include:^[6][10]

Before surgery: You might have chemotherapy or hormone therapy before surgery. This is called neo-adjuvant therapy. The main goal is to shrink the cancer before removing it.

Surgery: You might have breast-conserving surgery (which removes the cancer while leaving as much normal breast tissue as possible) or a mastectomy (an operation to remove the whole breast). If you have a mastectomy, you might be able to have breast reconstruction to create a new breast shape. You may also have surgery to remove lymph nodes in your armpit.^[6]

After surgery: You may have other treatments, including:

• Radiation therapy: Uses high-energy radiation to kill cancer cells
• Chemotherapy: Uses drugs (as a pill or through an IV) to kill cancer cells
• Hormone therapy: Blocks hormones like estrogen from reaching breast tissue
• Targeted therapy: Uses drugs that target specific features of cancer cells

Healthcare providers can often cure invasive ductal carcinoma if tests detect cancerous tumors before they spread to other areas of your body.^[1]

Possible complications

Invasive ductal carcinoma can spread (metastasize) to other areas of your body. The cancer can get into your bloodstream or lymphatic system and travel to distant organs. Common sites where breast cancer spreads include the liver, lungs, bones, and brain.^[1]