Types of Breast Cancer
There are many different types of breast cancer defined by where in the breast they begin to grow, how much they have grown or spread, and certain features that influence how the cancer behaves. The type of breast cancer you’ve been diagnosed with will help you and your doctor decide on the best treatment options for you.
Here, you can learn about the different types of breast cancer, the molecular subtypes of breast cancer, male breast cancer, and cancerous phyllodes tumors of the breast.
Invasive breast cancer
When breast cancer is called invasive (or infiltrating), it means it has spread into the surrounding breast tissue. The two most common types of invasive breast cancer are defined by where in the breast they begin to grow:
Invasive ductal carcinoma (IDC) is invasive breast cancer that starts in the milk ducts, the tubes that carry milk from the lobules to the nipple. It is the most common type of breast cancer; about 80% of all breast cancers are invasive ductal carcinomas.
Invasive lobular carcinoma (ILC) is invasive breast cancer that starts in the lobules, the glands in the breast that produce milk. It is the second most common type of breast cancer; about 10% of all invasive breast cancers are invasive lobular carcinomas.
Some types of invasive breast cancer have features that affect how they develop and how they are treated:
Triple-negative breast cancer is an aggressive type of invasive breast cancer that tests negative for estrogen receptors and progesterone receptors and doesn’t have extra HER2 proteins. About 12% of all invasive breast cancers are triple-negative.
Inflammatory breast cancer is a rare and aggressive type of invasive breast cancer. About 1% of all breast cancers in the United States are inflammatory breast cancer.
Metastatic breast cancer, also called stage IV breast cancer, is invasive breast cancer that has spread (metastasized) to parts of the body away from the breast, such as the bones, liver, lungs, or brain. Breast cancer can come back in another part of the body months or years after the original treatment (called a metastatic recurrence), but some people are initially diagnosed with metastatic disease (called de novo metastatic breast cancer).
Recurrent breast cancer is invasive breast cancer that has come back months or years after treatment. Breast cancer can recur in the same breast (local recurrence), nearby lymph nodes in the armpit or collarbone (regional recurrence), or in another part of the body, (metastatic or distant recurrence).
Male breast cancer is rare, but it does happen. Fewer than 1% of all breast cancers are diagnosed in men. Most male breast cancers are invasive ductal carcinomas.
Paget disease of the breast is a rare form of breast cancer where cancer cells collect in or around the nipple.
There are also five main molecular subtypes of invasive breast cancer based on the genes in the cancer tumor. The molecular subtype of a breast cancer can affect how the cancer is treated.
Non-invasive breast cancer
When breast cancer is called non-invasive (or in situ) it means it has not spread beyond the breast tissue where it started. Non-invasive breast cancers are also called precancers. There are two main types of non-invasive breast cancer:
Ductal carcinoma in situ (DCIS), is non-invasive breast cancer that has not spread outside the milk ducts where it started. DCIS isn’t life threatening, but is considered a precursor to invasive breast cancer and increases the risk of developing an invasive breast cancer later in life. About 16% of all breast cancer diagnoses are DCIS.
Lobular carcinoma in situ (LCIS), is non-invasive breast cancer that has not spread outside the lobules where it started. Despite its name, LCIS is a benign breast condition and is not a true breast cancer.
Cancerous phyllodes tumors of the breast
Phyllodes tumors of the breast are rare and make up fewer than 1% of all breast tumors. Most phyllodes tumors are benign (not cancerous), but about 25% are cancerous.
— Last updated on February 9, 2022, 11:36 PM