Understanding Invasive Ductal Carcinoma

When you are diagnosed with breast cancer, it can be challenging. There are different types and subtypes. Treatment and prognosis are associated with the different kinds of breast cancer. Learning more about the specific kind of breast cancer you have can help you understand your diagnosis and make informed decisions.

What is invasive ductal carcinoma?

Most breast cancers are invasive. This means the cancer has spread into surrounding breast tissue. Invasive ductal carcinoma is the most common kind of breast cancer. It is sometimes called infiltrating ductal carcinoma (IDC). Roughly 8 out of 10 breast cancers are IDC.¹

This cancer starts in the cells that line milk ducts. It then breaks through the duct wall and grows into nearby tissues. When it has reached this point, it may be able to spread to other areas of the body through the bloodstream and lymph system. This is called metastasis.¹

Less common kinds of invasive ductal carcinoma

There are other types of IDC that are less common. These include²:

• Medullary ductal carcinoma – This type of IDC may feel spongy instead of like a lump. It is a rare form that usually shows up on a mammogram.
• Mucinous ductal carcinoma – When cancer cells produce mucous, the cells and mucous combine to make a tumor.
• Papillary carcinoma – This type has finger-like projections called papules, which can be seen when cells are examined under a microscope. It mostly occurs in women over 60.
• Tubular ductal carcinoma –The cancer cells in this type look like tiny tubes. This is a very rare type.

How do you know if you have invasive ductal carcinoma?

IDC may not cause any symptoms initially. Sometimes an abnormality is found on a screening mammogram, leading to more testing. Other times, a lump may be found on self-exam. Signs or symptoms of IDC may include³:

• Swelling of all/part of the breast
• Skin irritation or dimpling
• Breast pain
• Nipple pain or the nipple turning inward
• Lump in the underarm area
• Nipple discharge
• Redness, scaliness, or thickening of the nipple or skin on the breast

Diagnosing IDC is typically done in a variety of ways. Diagnosis can involve⁴:

• Physical exam of the breast and underarm area
• Mammogram
• Ultrasound of the breast
• Breast MRI
• Biopsy

How is it treated?

Treatment for IDC can vary based on the stage and the exact subtype of the cancer. Many times a combination of therapies are used. Treatment may include²:

• Lumpectomy
• Mastectomy
• Sentinel node biopsy
• Axillary node dissection
• Breast reconstruction
• Radiation
• Chemotherapy
• Hormonal therapy drugs
• Biologic targeted therapy drugs

Depending on the stage and subtype of your cancer, you may have a variety of these treatments. Your doctor will explain to you which treatments are the best for your specific cancer and go over the risks and benefits for each one.

What is the outlook?

New treatments for breast cancer are being researched all the time. Your doctor can talk with you about your treatment options and clinical trial opportunities to help give you the best treatment for your cancer.