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Types of Breast Cancer

Education about breast cancer screenings and self-exams is now commonplace, but many people don't know about the types of breast cancer and how they differ. Breast cancer is not a one-size-fits-all type of disease, as you might think. From invasive ductal carcinoma to inflammatory breast cancer, each type is unique, behaving differently and requiring its own approach.

Learning about different types of breast cancer and how they work can help you make informed decisions, such as choosing the right cancer insurance. Read on to find out more about breast cancer and how it can be treated.

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What are the types of breast cancer?

Breast cancers may be classified based on factors like the cells and tissues they affect and whether they’re invasive or non-invasive. Here are a few types in more detail:

Invasive ductal carcinoma (IDC)

Invasive or infiltrating ductal carcinoma, or IDC, can start in the cells that line the milk ducts. It can spread outside the duct to other breast tissues. Over time, cancer cells may also spread to the lymph or blood vessels and metastasize to other parts of the body like the brain, lungs, liver, and bones. IDC is the most common breast cancer, and accounts for many cases of invasive breast cancer.1

Invasive lobular carcinoma (ILC)

Invasive lobular carcinoma starts (ILC) in the lobules, which are glands in the breast that produce milk. This invasive form of cancer may spread to other parts of the body unless diagnosed at an early stage. It can also be more likely to affect both breasts. That said, ILC may be less common than IDC, as only some cases of invasive breast cancer will be diagnosed as ILC. In addition to surgery that can remove the tumor, doctors may recommend other treatments.1

Inflammatory breast cancer (IBC)

Inflammatory breast cancer (IBC) is rare, accounting for a small percentage of all breast cancers. It is a type of invasive ductal carcinoma that involves cancer cells blocking lymph vessels in the skin, making the breast appear red, swollen, or inflamed. IBC does not typically cause a breast lump, and may also occur in women under 40. Treatments may involve a combination of surgery and radiation, chemotherapy, or targeted drug therapy.2

Paget’s disease of the breast

This is a rare cancer involving the nipple and areola (the darker-colored skin around the nipple). In many cases, Paget's disease of the breast is found alongside ductal carcinoma in situ (a non-invasive early-stage cancer) or invasive ductal carcinoma. Symptoms of this condition generally include a change in the appearance of the nipples or areola. The skin may be scaly and red, or the nipple may appear flat or inverted. If there's no lump, and a biopsy indicates the cancer has not spread within the breast, the outlook can be very good.3

Ductal carcinoma in situ (DCIS)

Also known as intraductal carcinoma or stage 0 breast cancer, ductal carcinoma in situ is a non-invasive pre-cancer or early-stage cancer. With this early form of cancer, most patients can be successfully treated, since the cancer cells that line the ducts have not spread into other breast tissue. Treatment usually includes surgery, such as a mastectomy, with appropriate medication.4

Invasive vs. non-invasive breast cancer

Breast cancer may be invasive or non-invasive depending on how cancer cells behave. The former can spread into neighboring tissues and travel through the lymph or blood vessels to other organs. The latter is largely contained to the lobules in the breast. In situ carcinomas are non-invasive and local, while invasive or infiltrating carcinomas can metastasize or spread to other organs.5

Types of breast cancer based on genes and hormones

Once doctors have conducted a biopsy, they can get more information about the specific type of cancer by studying cells from the tumor. Certain tests help doctors characterize a tumor as one of the following sub-types:

Hormone-receptor positive and negative

Breast cancer cells with either estrogen (ER) or progesterone (PR) receptors (or both) indicate hormone receptor-positive breast cancer. This cancer type has a better outlook as it grows slower than hormone receptor-negative cancer.6 It’s more common after menopause and may be treated using hormone therapy.5

Hormone receptor-negative breast cancer cells have no receptors for estrogen or progesterone, so hormone therapy drugs do not work for these cases. They grow faster than hormone receptor-positive cancers and are more commonly seen in women who aren't yet menopausal.6

HER2-positive and negative

HER2 (human epidermal growth factor receptor 2) is a protein that helps certain cancer cells grow faster. Some breast tumors contain elevated levels of this protein, which makes them HER2-positive breast cancers.7 These cancers may grow faster than HER2-negative cancer, but tend to respond well to treatments that specifically address the HER2 protein. HER2-negative cancers can be less likely to respond to HER2-targeting medicines.


Triple-negative breast cancer cells have no estrogen or progesterone receptors, nor are they high in the HER2 protein. Tests for progesterone, estrogen, and HER2 come up negative. This type of breast cancer is common among women under 40, and can grow and spread faster.8

What is metastatic breast cancer?

Invasive breast cancers may spread to other parts of the body if cancer cells enter the lymphatic system or the bloodstream. When breast cancer spreads to other regions of the body, like the liver, lungs, and brain, it is said to have metastasized.

Rather than a separate type of cancer, metastatic breast cancer is an advanced (late-stage) form of invasive cancer. Doctors may find metastatic cancer in patients who have already received treatment for earlier-stage breast cancer. This can happen even decades after the first instance of cancer and is known as distant recurrence or metastatic recurrence.9

How breast cancer can be treated

Treatment for breast cancer depends on the type and sub-type of breast cancer, as well as what stage it's in. Many women will undergo some sort of surgery to remove the tumor. You may already know that a mastectomy is the removal of an entire breast, but early-stage cancers may also be treated using breast-conserving surgery, which only removes a part of the breast.

Alongside surgery, doctors may recommend chemotherapy, hormone therapy, targeted drug therapy, immunotherapy, or radiation therapy. Treatment strategies may vary based on the patient's menopause status and overall health.10 Healthcare providers will also take your preferences and concerns into consideration, so you'll be able to play an active role in choosing your treatment plan.

Learn more about breast cancer

Understanding the different types of breast cancers and how they work can help you make better treatment and care decisions. It may help you spot the early signs of cancer and visit a doctor if you notice any breast abnormalities during a self-exam. Lastly, better knowledge of different types of breast cancers can give you a better idea of the kind of benefits you’ll need when seeking cancer insurance.

While your primary health insurance can help cover some treatment expenses, Aflac supplemental cancer insurance can be a safety net that helps you better manage medical costs and other essential and incidental expenses, such as rent, treatment travel, groceries, and medicine. Aflac offers various policy options to help suit the needs of different individuals and families, allowing you to choose the level of coverage and the benefits you want. With affordable rates, there's no reason to delay getting a quote.

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