Invasive Ductal Carcinoma (IDC)
Invasive ductal carcinoma (IDC), also called infiltrating ductal carcinoma, is the most common type of breast cancer. About 80% of all breast cancers are IDC, according to the American Cancer Society.
Invasive means the cancer has spread into surrounding breast tissues. Ductal means the cancer started in the milk ducts, the tubes that carry milk from the lobules to the nipple. Carcinoma refers to any cancer that begins in the skin or other tissues that cover internal organs, such as breast tissue. According to the American Cancer Society, about 281,550 new cases of invasive breast cancer will be diagnosed in women in 2021 and most of these will be IDC.
Normal breast with invasive ductal carcinoma (IDC) in an enlarged cross-section of the duct
Breast profile: A Ducts B Lobules C Dilated section of duct to hold milk D Nipple E Fat F Pectoralis major muscle G Chest wall/rib cage
Enlargement: A Normal duct cell B Ductal cancer cells breaking through the basement membrane C Basement membrane
Symptoms of invasive ductal carcinoma
In many cases, invasive ductal carcinoma causes no symptoms and is found after your doctor sees a suspicious area on a screening mammogram.
In other cases, you or your doctor may feel a lump or mass in your breast. Any of the following changes in the breast can be a first sign of invasive ductal carcinoma:
swelling of all or part of the breast
skin irritation
skin dimpling, sometimes looking like an orange peel
breast or nipple pain
nipple turning inward (retraction)
nipple discharge, other than breast milk
redness, scaliness, or thickening of the nipple or breast skin
a lump or swelling in the underarm area
Diagnosis of invasive ductal carcinoma
Diagnosing invasive ductal carcinoma involves a combination of procedures and almost always includes:
Other tests that may be used are:
Staging invasive ductal carcinoma
The stage of invasive ductal carcinoma is determined by the cancer’s characteristics, such as how large it is and whether or not it has hormone receptors. The stage of the cancer helps you and your doctor:
figure out your prognosis, which is the likely outcome of the disease
decide on the best treatment options for you
determine if certain clinical trials may be a good option for you
Generally, the stage of invasive ductal carcinoma is described as a number on a scale of I through IV. Stages I, II, and III describe early-stage cancers, and stage IV describes cancers that have spread outside the breast to other parts of the body, such as the bones or liver.
Once invasive ductal carcinoma has been diagnosed, your doctor will do more tests to collect information on the characteristics of the cancer. These tests, as well as the results of your biopsy, make up the parts of your pathology report.
Information commonly collected as part of a pathology report includes:
size of the breast cancer
Nottingham grade of the cancer
tumor necrosis
tumor margins
lymphovascular invasion
lymph node status
hormone receptor status
HER2 status
rate of cell growth (Ki-67 levels)
Treatment of invasive ductal carcinoma
Treatments for invasive ductal carcinoma may include:
surgery: You and your doctor will work together to determine the type of surgery that’s right for you, based on the characteristics of the cancer, your family and medical history, and your preferences.
radiation therapy: Radiation therapy is almost always recommended after lumpectomy and may be recommended after mastectomy if the cancer is large or if cancer is found in the lymph nodes.
chemotherapy: Chemotherapy may be given before or after surgery. Your doctor will consider the characteristics of the breast cancer and your medical history when deciding if chemotherapy is right for your unique situation.
hormonal therapy: If the breast cancer has receptors for the hormones estrogen, progesterone, or both, your doctor likely will recommend hormonal therapy, which is also called anti-estrogen therapy or endocrine therapy. Hormonal therapy medicines work by lowering the amount of estrogen in the body or by blocking the action of estrogen on breast cancer cells.
targeted therapy: Targeted cancer therapies are treatments that target specific characteristics of cancer cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way. Some targeted therapies are antibodies. Antibodies are proteins made naturally by your immune system that find and attack foreign invaders, such as germs that cause infection. These types of targeted therapies work just like the antibodies made naturally by your immune system, and are sometimes called immune targeted therapies.
immunotherapy: Immunotherapy medicines use your body’s immune system to attack cancer cells. The characteristics of the cancer will determine if immunotherapy is a treatment option for you.
Survivorship care after invasive ductal carcinoma treatment
Because of better diagnostic tests and advances in cancer treatments, more people are living longer than ever after being diagnosed with any type of cancer, including breast cancer. Experts estimate that there are more than 3.8 million breast cancer survivors in the United States.
Still, because of treatments they’ve received, many breast cancer survivors have a higher risk of developing other diseases as they age, including high blood pressure, heart disease, and osteoporosis. To make sure breast cancer survivors are regularly screened for these and other diseases, experts have developed the idea of survivorship care planning.
Survivorship care plans are written documents made up of two parts.
The first part is a treatment summary, a record of all the breast cancer treatments you’ve received.
The second part is basically a roadmap of what you can expect in the years after treatment, including any late or long-term side effects you might have, and a schedule of how you’ll be monitored for these side effects and other health conditions. This part of the survivorship care plan usually includes:
the tests you’ll have
which doctors will order the tests
a schedule of when the tests will be done
healthy living recommendations
resources, if you need more information
Learn more at Before Treatment: Planning Ahead for Survivorship.
Subtypes of invasive ductal carcinoma
There are several rare subtypes of invasive ductal carcinoma. These are often named for features seen when the cells are looked at under a microscope, such as the way the cells are arranged. The symptoms, diagnosis, staging, treatment options, and survivorship care are generally the same for all IDC subtypes.
Learn more about the following IDC subtypes below:
Tubular carcinoma of the breast
Medullary carcinoma of the breast
Mucinous carcinoma of the breast
Papillary carcinoma of the breast
Cribriform carcinoma of the breast
Metaplastic carcinoma of the breast
Tubular carcinomas of the breast account for less than 2% of all breast cancers. When looked at under a microscope, the cells of a tubular carcinoma look like tubes. These tumors tend to be low-grade, meaning that their cells look somewhat similar to normal, healthy cells, and tend to grow slowly. Tubular carcinomas are usually hormone receptor-positive and HER2-negative.
Medullary carcinomas of the breast account for less than 5% of all breast cancers. It is called “medullary” carcinoma because the tumor is a soft, fleshy mass that resembles a part of the brain called the medulla. Medullary carcinomas are more common in women who have a BRCA1 mutation. Also, medullary carcinomas are often triple-negative, which means they are estrogen receptor-negative, progesterone receptor-negative, and HER2-negative. But unlike most triple-negative breast cancers, which tend to be more aggressive, medullary carcinoma doesn’t grow quickly and usually doesn’t spread outside the breast to the lymph nodes. Medullary carcinoma cells are usually high-grade in their appearance and low-grade in their behavior. In other words, they look like aggressive, highly abnormal cancer cells, but they don’t act like them.
Mucinous carcinomas of the breast — also called colloid carcinomas — account for less than 2% of all breast cancers. In mucinous carcinoma, the tumor is made up of abnormal cells that “float” in pools of mucin, a key ingredient in mucus. Mucinous carcinomas are usually low-grade, meaning the cells look somewhat similar to healthy cells, and usually don’t spread outside the breast to the lymph nodes. Mucinous carcinomas are usually hormone receptor-positive and HER2-negative.
Papillary carcinomas of the breast account for less than 1% of all breast cancers. When the cells are looked at under a microscope, they have finger-like projections or “papules.” Papillary carcinomas are usually small, hormone receptor-positive, and HER2-negative. In most cases of papillary carcinoma, ductal carcinoma in situ (DCIS) is also present. DCIS is non-invasive breast cancer that has not spread outside the milk ducts where it started.
Cribriform carcinomas of the breast account for less than 1% of all breast cancers. In invasive cribriform carcinoma, the cancer cells invade the stroma (connective tissues of the breast) in nestlike formations between the ducts and lobules. Within the tumor, there are distinctive holes in between the cancer cells, making it look something like Swiss cheese. Invasive cribriform carcinoma is usually low grade, meaning that its cells look and behave somewhat like normal, healthy breast cells.
Metaplastic carcinomas of the breast account for less than 1% of all breast cancers. Metaplastic breast cancers contain abnormal ductal cells, but also contain cells that look like the soft tissue and connective tissue in the breast. The ductal cells have changed their form to become completely different cells, though it’s not clear how or why this happens. When cells change form it’s called metaplasia, which gives this type of breast cancer its name. Metaplastic breast cancer is considered more aggressive and is usually high grade and triple-negative, meaning it is estrogen receptor-negative, progesterone receptor-negative, and HER2-negative.
— Last updated on June 29, 2022, 3:08 PM
