There’s no one-fits-all type of diagnosis.
Just like breasts themselves, breast cancer can come in many different forms — there’s no one-fits-all type of diagnosis just like there’s no one-size-fits-all bra.
If you or a loved one is battling breast cancer, knowing all the different forms the disease can take is key to understanding a prognosis and what treatment options are available. But there are so many variations of breast cancer and so many ways to describe each classification, keeping it all straight can feel overwhelming. But don’t worry — we’re here to help.
According to the American Cancer Society, the disease is classified based on which cells the cancer has spread to, how far it’s progressed, and in some cases how it behaves within the body. It can be “ductal” (meaning the cancer’s confined to the milk ducts) or “lobular” (in the breast’s lobules, or the glands that produce milk). It can be invasive, “in situ” (Latin for “in its original place”), inflammatory, and more.
Here’s a breakdown of the different types of breast cancer, what to know about each variation, and how they’re treated.
Most Common Forms of Breast Cancer
Ductal Carcinoma In Situ
Ductal carcinoma in situ (DCIS) is a very early form of breast cancer. As its name suggests, DCIS is noninvasive and confined to the milk ducts. It’s usually detected during a mammogram and those with it don’t typically have any symptoms, though occasionally patients may notice a breast lump or bloody discharge from the nipple, according to the Mayo Clinic.
In some women, DCIS may never progress to invasive cancer, which has led some to question whether those with a low-risk form of the disease need to be treated at all, per Memorial Sloan Kettering Cancer Center. But currently, DCIS is treated with either a lumpectomy or mastectomy.
Invasive Ductal Carcinoma
This cancer starts in the milk ducts and has spread to surrounding tissue. From there, the cancer has the potential to move to other parts of the body through the lymph system and bloodstream. About 75 percent of the 245,000 women diagnosed with breast cancer each year have invasive ductal carcinoma (IDC), making it the most common form of the disease.
A doctor may recommend surgery, chemotherapy, radiation, hormone therapy — or some combination of these methods, Pamela Wright, M.D., medical director of the Breast Center at Johns Hopkins’ Suburban Hospital says: “Treatment is based on the size and location of the cancer cells, the features or characteristics of the cells, and the staging.”
Invasive Lobular Carcinoma
Invasive lobular carcinoma (ILC) is the second most common form of invasive breast cancer, making up about 10 percent of cases. ILC originates in the breast lobules and has the potential to spread to other parts of the body. Because ILC doesn’t always form a lump, it can be harder to detect in a physical exam or in mammograms than IDC. Women who have it may notice that part of their breast feels fuller or thicker than the rest of the tissue, a nipple that turns inward, or a change in the texture of the breast skin, breast surgeon Hanh-Tam Tran, M.D. says.
Depending on the size and location of the tumor, surgery may be recommended, but hormone therapy “is almost always part of the plan for treating lobular cancers,” Dr. Tran says. “Invasive lobular carcinomas are usually strongly estrogen receptor-positive, which makes them very responsive to anti-hormonal medications like tamoxifen.”
HER2-Positive and HER2-Negative
HER2 stands for human epidermal growth factor receptor-2, a protein that helps control how breast cells grow and divide. About 20 percent of breast cancer patients overproduce HER2, which leads cells to multiply too quickly. These women have what’s known as HER2-positive breast cancer, which tends to spread fast and has a high chance of recurring. It can also be treated effectively with drugs that target HER2 proteins.
Women with cancer cells that don’t overproduce HER2 are considered HER2-negative. This cancer usually grows slower than HER2-positive cases and is less likely to spread to other parts of the body.
Triple-Negative Breast Cancer
Triple-negative breast cancer (TNBC) refers to how the cancer cells present in this form of the disease don’t have estrogen or progesterone receptors and also don’t overproduce HER2. (They test “negative” on all three tests.)
Because of this, treatment options for TNBC are more limited than for other types of breast cancer. Surgeon Bonnie Sun, MD, says “chemotherapy is almost always called for” to shrink tumors or make them less aggressive. Radiation and surgery may also be recommended.
TNBC accounts for 10 to 15 percent of cases. It tends to grow and spread faster than other types of breast cancer and the prognosis is typically worse. This cancer also tends to be more common in women under 40, among Black patients, and in those with the BRCA mutation — a genetic condition that increases the risk for certain cancers.
Inflammatory Breast Cancer
Inflammatory breast cancer (IBC) is rare, making up only 1 to 5 percent of breast cancer cases. IBC is a special type of invasive ductal carcinoma, which causes the breast to become swollen, and red, and in some cases, the skin may appear dimpled, like an orange peel. This occurs because the cancer cells block lymph vessels in the skin, making the breast appear “inflamed,” according to the American Cancer Society.
IBC also tends to impact younger women, Black patients, and those at an unhealthy weight. It’s an aggressive cancer, and the outcomes for women are generally worse compared to other breast cancers.
Treatment usually begins with chemotherapy to shrink the tumor and is then followed by mastectomy (lumpectomies are rarely recommended because this cancer grows so quickly). Radiation or more chemotherapy is typically recommended after surgery.
Other Rare Forms of Breast Cancer
Paget disease of the breast makes up just 1 to 3 percent of cases. People with this cancer may notice bloody or yellow-colored discharge from their nipple, and that the skin of the areola looks red and scaly. In up to 90 percent of these cases, DCIS or IDC are found. Surgery and radiation therapy are normally recommended for this cancer.
Angiosarcoma of the breast is seen in less than 1 percent of breast cancer patients. It originates in the cells that line the blood vessels of lymph vessels, and according to the American Cancer Society, is usually a complication of previous breast radiation treatment. This cancer is aggressive and mastectomies are usually called for.
Metaplastic breast cancer is a type of invasive breast cancer that begins in the milk duct and contains a mix of two or more types of breast cancer cells. Researchers believe that cells within these tumors take on one form (like a ductal cell) and turn into another (like a cell from the connective tissue of the breast). This cancer behaves aggressively and treatment options include surgery, radiation, and hormone therapy.
Phyllodes tumors develop in the connective tissue of the breast — not the ducts or glands, where most breast cancers begin. These tumors feel like a firm lump, which grows fairly quickly. The large majority of Phyllodes tumors are benign. Patients with a malignant tumor usually undergo surgery, followed by radiation therapy.
