Invasive vs. non-invasive breast cancer types
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 tumor’s size, its hormone-receptor status and whether the cancer had spread to the lymph nodes. Learn more about breast cancer recurrence.
Types of invasive breast cancer
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.
Invasive ductal 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
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
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.
Paget’s disease of the breast
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 of the breast
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 developangiosarcoma, 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.
Noninvasive (in-situ) types of breast cancer
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.
Ductal carcinoma in situ (DCIS)
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.
Lobular carcinoma in situ (LCIS)
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.