Types of Breast Cancer

Types of Breast Cancer

Memorial Sloan Kettering medical oncologist Andrew Seidman discusses treatment options with a breast cancer patient.

MSK medical oncologist Andrew Seidman is part of a team of experts who are dedicated to providing personalized, compassionate care for people with breast cancer.

There are several types of breast cancer. This information describes them and explains how we classify (sort) them into each type.

To find out what type of breast cancer you have, we look at a sample of your cells under a microscope. We collect this sample during your breast biopsy or breast cancer surgery.

We classify breast cancer types by factors that help predict the best treatment for that kind of cancer. We look at whether the cancer:

  • Is sensitive to 2 hormones, called estrogen and progesterone.
  • Has proteins that play a role in breast cancer growth, such as HER2.
  • Has a genetic makeup that affects treatment options.

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Please use this guide to learn more about the types of breast cancer.

What is invasive breast cancer, noninvasive breast cancer, and metastatic breast cancer?

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Noninvasive cancer is cancer that has not spread beyond the tissue where it started. Noninvasive breast cancer means the abnormal cells are only in the milk ducts of the breast. They cannot spread to nearby tissue or to other parts of the body.

Invasive breast cancer means the cancer has grown beyond the place where it started. It’s in nearby normal breast tissue and can spread to other parts of the body.

Metastatic breast cancer is also called advanced breast cancer, or stage 4 breast cancer. It’s invasive cancer that has spread from the breast. It can spread to the skin, lymph nodes, or to other areas, such as the liver, lungs, or bones.

Some people have metastatic cancer when they’re first diagnosed. More often, you get advanced breast cancer when the disease comes back somewhere else in the body, even after you had treatment.

Here are some other words you may hear to describe breast cancer.

  • Carcinoma (KAR-sih-NOH-muh) means cancer that starts in the cells that line the inner or outer surfaces of tissues, including breast ducts. 
  • In situ (in SY-too) are words in Latin that mean “in its original place.”
  • Ductal means cancer that’s only in the milk ducts.
  • Lobules (LAH-byools) are small round sacs that make breast milk.

What is invasive ductal carcinoma?

Invasive ductal carcinoma starts in the milk ducts and spreads to nearby tissue. It’s the most common type of breast cancer. Out of every 10 cases of breast cancer, 7 to 8 of them are invasive ductal carcinoma.  

What is ductal carcinoma in situ?

Ductal carcinoma in situ (DCIS) is a very early form of breast cancer. It’s the most common type of noninvasive breast cancer.

DCIS is classified (graded) as low, intermediate, or high. Grades are based on what the cells look like under a microscope. A lower grade means DCIS looks more like normal breast cells. The higher the grade, the more it looks different from normal cells.

DCIS sometimes involves the nipple, making it look red and scaly. This is a rare form of cancer called Paget’s disease of the breast (or of the nipple).

DCIS may not become invasive cancer, but researchers are still trying to learn how often that happens. They want to know if people can avoid treatment if it’s unlikely DCIS will become invasive cancer.

For now, the standard treatment for DCIS includes surgery, often a lumpectomy. For most people with DCIS, surgery is the only way to tell for sure if you also have invasive cancer.

What is invasive lobular carcinoma?

Invasive lobular carcinoma (ILC) starts in the breast’s lobules. This cancer spreads to nearby tissue. ILC is the second most common type of invasive breast cancer, after invasive ductal carcinoma. Out of every 100 cases of breast cancer, 10 to 15 are ILC.

People who have ILC may notice a thick or full area that does not feel like the rest of the breast. ILC doesn’t always form a lump.

What is lobular carcinoma in situ? What is atypical lobular hyperplasia?

Lobular neoplasia (LAH-byoo-ler NEE-oh-PLAY-zhuh) is when there are abnormal cells in the breast’s lobules. It rarely becomes cancer. Types of lobular neoplasia include:

  • Lobular carcinoma in situ (LCIS) (LAH-byoo-ler KAR-sih-NOH-muh in SY-too), a condition that is not breast cancer or a precancer. Often, it does not become invasive cancer if it’s not treated.
  • Atypical lobular hyperplasia (ALH) (ay-TIH-pih-kul LAH-byoo-ler HY-per-PLAY-zhuh), a condition that is not cancer. It’s when there are more cells than usual in your breast’s lobules. The extra cells are abnormal.

Both LCIS and ALH raise your risk of getting breast cancer in the future. If you have been diagnosed with either of them, talk with your doctor. Ask how often you should be screened for breast cancer and if you should have more screening tests.

What are hormone receptor-positive, estrogen receptor-positive, and progesterone receptor-positive breast cancer?

We test breast cancer cells to see if they have receptors for 2 hormones, estrogen and progesterone. Receptors are proteins on cells that attach to certain substances, including estrogen and progesterone. These 2 hormones can help cancer grow.

Breast cancer can have receptors for estrogen, progesterone, both, or neither. Hormone receptor positive breast cancer has either estrogen or progesterone receptors. Breast cancer is also:

  • Estrogen receptor positive, or ER positive, if it has receptors for estrogen.
  • Estrogen receptor negative, or ER negative, if it does not have receptors for estrogen.
  • Progesterone receptor positive, or PR positive, if it has receptors for progesterone.
  • Progesterone receptor negative, or PR negative, if it does not have receptors for progesterone.

Hormone therapy is a drug or drugs that block estrogen and progesterone from plugging into receptors. This cuts the cancer off from hormones that could help it grow.

Your treatment may include hormone therapy if the cancer is:

  • ER positive.
  • PR positive.
  • Both ER positive and PR positive.

What is HER2-positive breast cancer?

HER2-positive breast cancer is cancer that tests positive for a protein called HER2. This protein helps control the growth of healthy breast cells. HER2/neu is a gene that acts like an on/off switch to make HER2.

In about 1 out of every 5 cases of breast cancer, there’s either extra copies of the HER2/neu gene, or too much HER2. This is called HER2-positive breast cancer. Treatment for HER2-positive breast cancer is targeted therapy drugs.

What is HER2-negative breast cancer? What is HER2-low breast cancer?

HER2-negative cancers make up many kinds of cancers. A lot of them have low levels of the HER2 protein, so they’re called HER2-low breast cancer. About half of all breast cancers are HER2-low.

In the past, the only treatments for HER2-low breast cancer were the same as for HER2-negative. This changed in August 2022, when the U.S. Food and Drug Administration approved the first targeted therapy for HER2-low metastatic breast cancer. It’s for HER2-low breast cancer that has spread to other body parts and cannot be removed with surgery.

The targeted therapy drug is called trastuzumab deruxtecan (T-DXd). MSK breast medical oncologist Shanu Modi led the research study, also known as a clinical trial, testing this drug.

What is triple-negative breast cancer?

Out of every 100 cases of breast cancer, about 10 to 15 are triple negative. This means they test “negative” for the 3 receptors for estrogen, progesterone, and HER2.

Receptors are proteins on cells that attach to certain substances, including the hormones estrogen and progesterone. These 2 hormones can help cancer grow.

In triple-negative breast cancer, there are no receptors for estrogen or progesterone. There also are no receptors for HER2, a protein helps control the growth of healthy breast cells.

Triple-negative breast cancer can be harder to treat. It does not respond to drugs that target estrogen, progesterone, or HER2 receptors. Triple-negative breast cancer mainly is treated with chemotherapy. Some people may be able to join research studies, also known as clinical trials.

Inherited genetic mutations (changes) are more common with triple-negative breast cancer. This is true even if there’s no history of breast cancer in your family. When we say family, we mean family members related to you by blood. They are not related to you through marriage or adoption.

If you have triple-negative breast cancer, talk with your doctor about genetic counseling and testing. They will look for hereditary forms of breast cancer. This kind of breast cancer is inherited (passed down from your parents). It includes cancers linked to the BRCA1 and BRCA2 genes and other genetic mutations.

Your doctor can find the best treatment plan for you if they know you have a genetic mutation. People related to you by blood also may also be at risk for cancer.

What are the stages of triple-negative breast cancer?

Stage 0 triple-negative breast cancer
  • There are abnormal cells but they have not spread to nearby tissue.
Stage 1 triple-negative breast cancer
  • Cancer has spread to other tissue in a small area.
Stage 2 triple-negative breast cancer
  • The cancer is invasive, but the tumor is still localized and has not spread beyond the breast. It’s between 20 and 50 mm (0.70 and 1.97 inches). It has spread to some lymph nodes. Or, the tumor is more than 50 mm but has not spread to lymph nodes.
Stage 3 triple-negative breast cancer
  • The cancer is regional. It’s more than 50 mm (1.97 inches). It’s spread to more lymph nodes over a larger area. In some cases, there’s no tumor.
Stage 4 triple-negative breast cancer
  • This is metastatic cancer that has spread beyond the breast to other parts of the body.

What is inflammatory breast cancer?

Inflammatory breast cancer (IBC) often causes the breast to become red, swollen, and warm. Your breast skin may look thickened or discolored. It may have tiny dimples, puckers, or ridges that make it look like the skin of an orange.

Symptoms can look like an infection, but they’re caused by cancer blocking lymphatic vessels in the skin and breast tissue. This starts a buildup of fluid (lymph) that can cause pain, discoloration (a change in color), and a sudden swelling of the breast.

IBC is called locally advanced breast cancer. It can spread quickly and should be treated right away.

Learn about our Inflammatory Breast Cancer team

What is a breast papilloma? Is a breast papilloma cancer?

A breast papilloma is a small, wartlike growth in the breast’s milk ducts. It’s also called intraductal papilloma. This benign (not cancer) condition can cause a clear or bloody discharge from the nipple. You also may feel a small lump behind or next to the nipple. Having 1 papilloma does not raise your breast cancer risk. If you have several of them, you may be at higher risk. 

What is metaplastic carcinoma?

Metaplastic carcinoma (meh-tuh-PLAS-tik KAR-sih-NOH-muh) is a rare type of invasive breast cancer. It has a mix of 2 or more kinds of breast cancer cells, usually carcinoma and sarcoma. It’s also called metaplastic breast cancer. Metaplastic means cancer that starts in cells that have changed into another kind of cell.

To treat metaplastic carcinoma, we first learn more about its genetics and biology. We find out if the tumor is more similar to carcinoma or sarcoma, because they have very different treatments.

What is breast sarcoma?

Breast sarcoma is a very rare form of breast cancer. It does not start in the lobes or ducts. Instead, a tumor can form in the connective or fibrous tissue around them. Only 1 out of every 100 cases of breast cancers are breast sarcoma.

What is male breast cancer?

Breast cancer in men is more likely to be cured if it’s found early. Many people assigned male at birth don’t know they can get breast cancer. Often, they don’t talk with their healthcare provider when they find a mass or lump in their breast. The most common symptom of male breast cancer is a lump that can be felt in the breast. MSK has more information about symptoms, diagnosis, and treatment of male breast cancer