This page was reviewed under our medical and editorial policy by
Daniel Liu, MD, Plastic and Reconstructive Surgeon
This page was reviewed on February 18, 2022.
There are dozens of types and subtypes of breast cancer. To determine an appropriate approach to treating breast cancer, your doctor will first evaluate the specifics of the breast tumor, including:
Most types of breast cancers are adenocarcinomas of the breast. These types of tumors are found in many other common cancers and form in glands or ducts that secrete fluid. Breast adenocarcinomas form in milk-producing glands called lobules or in milk ducts.
Breast cancer occurs in two broad categories: invasive and noninvasive. Some are slow-growing, while others are more aggressive. A number of factors influence how aggressive a tumor is, including its biological makeup, size, stage, etc. But generally speaking, the most aggressive types of breast cancer tend to be inflammatory breast cancer and angiosarcoma of the breast, while ductal carcinoma in situ, lobular carcinoma in situ and phyllodes tumors tend to be more slow-growing.
Certain subtypes of breast cancer, such as triple-negative breast cancer and inflammatory breast cancer, are also more likely to recur despite aggressive treatment. Many variables may determine when and whether a specific breast cancer recurs, including the original breast tumor’s size, its hormone-receptor status and whether the cancer had spread to the lymph nodes. Learn more about breast cancer recurrence.
Most breast cancers are invasive, meaning the cancer has spread from the original site to other areas, like nearby breast tissue, lymph nodes or elsewhere in the body. Invasive (infiltrating) breast cancer cells break through normal breast tissue barriers and spread to other parts of the body through the bloodstream and lymph nodes. The two most common types of invasive breast cancer are invasive ductal carcinoma and invasive lobular carcinoma.
The most common type of breast cancer—accounting for roughly 70 to 80 percent of all cases—is called invasive ductal carcinoma (IDC). IDC is a cancer that starts in a milk duct (the tubes in the breast that carry milk to the nipple) and grows into other parts of the breast. With time, it may spread further, or metastasize, to other parts of the body.
Invasive lobular carcinoma (ILC) is the second most common type, accounting for roughly 5 to 10 percent of all breast cancers. ILC starts in lobules (where breast milk is made) and then spreads into nearby breast tissue. Like IDC, it may metastasize. However, this cancer is harder to detect on mammograms and other exams than IDC. One in five women with ILC have both breasts affected.
Inflammatory breast cancer, which may be detected in the ducts or lobules, tends to spread faster than other types of breast cancer. This quick-growing, aggressive disease makes up about 1 to 5 percent of breast cancers in the United States, according to the NCI. It gets its name from the inflammatory signs it causes, usually redness and swelling on the surface of the breast. Because of these signs, it’s often misdiagnosed as a breast infection. In fact, for one out of three patients with this type of cancer, it’s not diagnosed until more advanced stages of the disease when it’s already metastasized to other areas of the body, according to the American Cancer Society (ACS). For these reasons, inflammatory breast cancer has a lower survival rate.
Also known as Paget’s disease of the nipple, Paget's disease of the breast is a much less common type of breast cancer. It primarily affects about 1 to 4 percent of patients also diagnosed with another breast cancer, according to the NCI. It develops in the skin of the nipple and the areola, creating unique tumor cells called Paget cells.
Angiosarcoma is breast cancer that forms in the lining of lymph or blood vessels. It’s rare and accounts for only 1 to 2 percent of all sarcomas (including those found anywhere else in the body), according to the NCI. Though anyone may develop angiosarcoma, it’s most common in people older than 70. It’s frequently caused by complications from radiation therapy to the breast, but it may not occur until eight to 10 years later. Angiosarcoma is a type of cancer that grows quickly and often isn’t diagnosed until it’s already spread to other areas of the body.
Phyllodes tumors are rare and are found in the connective tissues of the breast. This type of tumor mostly affects women in their 40s, though it may develop in patients of all ages. People who have an inherited genetic condition called Li-Fraumeni syndrome are at an increased risk for this type of tumor. About 25 percent of phyllodes tumors are cancerous, according to the ACS.
Other, even more rare, types of invasive breast cancer include adenoid cystic carcinoma, low-grade adenosquamous carcinoma, medullary carcinoma, mucinous carcinoma, papillary carcinoma and tubular carcinoma.
In situ breast cancer cells are non-invasive and remain in a particular location of the breast, without spreading to surrounding tissue, lobules or ducts.
Breast cancer that does not spread beyond the milk ducts or lobules is known as in situ. The two types of in situ cancers are ductal carcinoma and lobular carcinoma.
About 20 percent of newly diagnosed breast cancers are classified as DCIS, according to the ACS. DCIS starts out as a mass that grows in a milk duct, which carries milk from the lobules, or glands, to the nipple. A DCIS hasn’t spread to other parts of the body. Over time, chances increase for the mass to break through the ductal walls into the surrounding tissue and fat of the breast. With advances in diagnostics and treatments, however, most patients treated for DCIS, also called stage 0 breast cancer, have positive outcomes.
An LCIS is technically not considered cancer, but rather a change in the breast. In the breast are tens of thousands of tiny clusters of lobules to produce breast milk. Cells that resemble cancer cells may grow inside these lobules. LCIS tends to remain there and not spread. However, having LCIS puts you at an increased risk for invasive breast cancer, so your care team may want to monitor you in order to promptly address any changes.
Genomic research has also led to a more specific classification of breast cancers, based on their genes and proteins. Sixty percent of breast cancers are estrogen-positive, for example, while 20 percent are HER2-positive, and another 20 percent are triple-negative.
Hormone receptor status refers to whether or not breast cancer cells have specific proteins that act as “receptors” for the hormones estrogen and progesterone. Hormone-receptor status is determined by testing breast cancer cells removed during a biopsy or surgery.
If breast cancer cells have hormone receptors, then the cancer is hormone receptor-positive, which means the hormones estrogen (“ER-positive”) and progesterone (“PR-positive”) are responsible for fueling the cancer’s growth. These represent 60 to 75 percent of breast cancers, according to the American Society of Clinical Oncology (ASCO).
If there are no receptors, the cancer is hormone receptor-negative. These cancers tend to grow at a faster rate than hormone receptor-positive cancers.
A cancer’s hormone receptor status influence how it’s treated because inhibiting the hormones from attaching in hormone receptor-positive cancers may help keep it from spreading. Clinical trials have resulted in many innovative drugs in this area.
Download breast cancer infographic »
Breast cancers may also be HER2-positive or HER2-negative depending on the levels of a growth-promoting protein called HER2 within the cancer cells. HER2-positive breast cancers have high levels of the HER2 protein, which means they’re more likely to be fast-growing than some other types of breast cancer, but they may also be treated with drugs specifically designed to target the HER2 protein. Cancers that are HER2-negative don’t respond to the same drugs. Cancers that rely on human epidermal growth factor receptor 2 (HER2) to grow (HER2-positive) are found in 15 to 20 percent of invasive breast cancers.
A cancer that’s hormone receptor-negative and HER2-negative is called triple-negative. These tend to grow and spread at a fast rate. This disease more often affects younger women, women of African-American descent and women with the BRCA-1 gene mutation.
When a tumor doesn’t express any of these three proteins, it’s considered a triple-negative breast cancer. About 15 percent of all invasive breast cancers are triple-negative, according to ASCO. This cancer is more common in younger women. Women who carry the BRCA1 gene mutation also tend to have a higher chance of developing triple-negative breast cancer.
Stage 4 breast cancer is metastatic, meaning it’s spread to another part or parts of the body. If doctors find breast cancer cells in the liver, for example, the disease is classified as breast cancer that has metastasized to the liver, not liver cancer per se. These cancer cells also commonly travel to the lungs, brain or bones, as well as to lymph nodes. Metastatic breast cancer may be diagnosed initially, or it may develop months or years after detection of the initial cancer. While many other types of cancer have strong, positive outcomes with no evidence of disease or recurrence, metastatic breast cancer patients have to undergo treatment for the rest of their lives. The goal is to control further spread while giving the patient a good quality of life.
Almost every cell in the body has the potential to become cancerous. While most breast cancers occur in women, men have breast tissue, too, and it can develop breast cancer.
One out of 100 breast cancers in the United States is found in a man, according to the U.S. Centers for Disease Control and Prevention. The most common types of breast cancer in men are the same as for women: invasive ductal carcinoma and invasive lobular carcinoma. A man’s risk for breast cancer increases if he has a family history of breast cancer or a gene mutation such as BRCA2. Learn more about the similarities and differences of breast cancer in men and women.
Next topic: What are common types of breast cancer?
