The Many Types of Breast Cancer

Types of breast cancer depend on factors like where the tumor starts. Symptoms and treatment options can differ, based on the type of cancer.

Hearing “you have breast cancer” can be frightening. But if you face that diagnosis, learning about the specific kind of breast cancer you have can help you understand your condition and your treatment options.

And because there are many types of breast cancer, prevention should include knowing the sometimes surprising symptoms of various kinds of breast malignancies. For example, although breast lumps are frequently important warning signs of cancer, that’s not always the case. In fact, some types of breast cancer may not have an obvious lump and may even look like a skin infection.

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Breasts are made up of fat, connective tissue, milk glands known as lobules, milk ducts that carry the milk to the nipples, and lymph nodes. Types of breast cancer depend on where in these breast areas a malignancy starts, as well as whether or not the cancer responds to hormones and other factors.

Most breast cancers begin in epithelial cells — cells lining tissues and organs — and are called carcinomas. Other types of breast cancers, sarcomas, originate in the cells of the muscle, fat, or connective tissue. Some breast tumors are actually combinations of different types of cancer.

In addition, many specific factors influence how a specific case of breast cancer, no matter what type, is treated and the likelihood of a successful outcome. Biopsies and other tests reveal whether there is lymph node involvement, the stage of breast cancer (stages range from non-invasive stage 0 to metastatic stage IV, which has spread to other areas), and whether the tumor responds positively or negatively to the influence of hormones.

The most common types of breast cancer

Of all the types of breast cancer, ductal carcinoma, which begins in milk duct cells, is the most common, according to the National Cancer Institute. But while one form of milk duct cancer is rarely life-threatening, another type needs aggressive treatment.

Ductal carcinoma in situ (DCIS), also called stage 0 breast cancer, is sometimes labeled a pre-cancer. About one in five women diagnosed with a new breast cancer have this type — and the good news is it’s virtually always curable.

DCIS is also known as non-invasive or pre-invasive breast cancer because, while abnormal cells lining the milk ducts have developed the characteristics of cancer, these cells haven’t spread past the walls of the ducts into the nearby breast tissue. DCIS rarely metastasizes to other parts of the body. However, because there’s no way at this time for doctors to know for certain DCIS won’t become invasive, the American Cancer Society recommends DCIS should be treated.

Treatment varies based on the individual case but may include breast-conserving surgery, radiation, and treatment with the drug tamoxifen, if the cancer is hormone receptor positive.

Invasive ductal carcinoma (IDC) is the most common of all types of breast cancer, accounting for about 80 percent of breast malignancies. It grows through the wall of a milk duct and into the fatty tissue of the breast. Symptoms may include a lump or thickening in the breast, new pain in one breast, dimpling, or other changes in a nipple or swelling in one breast — or no symptoms at all. Mammograms are a good way to detect this form of cancer early; biopsies then determine if a lump is IDC.

There are several types and sub-types of this common breast cancer. For example, mucinous ductal carcinoma tumors are formed from mucous-containing cancer cells, and this type of IDC carries a better prognosis than some other forms of the disease. Papillary ductal carcinoma is another type of IDC — it’s more common in women 50 and older and rarely becomes invasive.

Treatment for IDC depends on how large the tumor is and if it has spread, the exact type of IDC and whether it responds to hormone therapy. IDC treatment typically involves surgery and, depending on the type and stage of the cancer, chemotherapy, radiation, or biologic targeted therapy.

About one in 10 breast cancers are invasive lobular carcinomas, which begin in the milk producing lobules and, like IDC, can spread to other areas of the body. Invasive lobular carcinoma (ILC) may be harder to detect on a mammogram than invasive ductal carcinoma because it’s less likely than other types of breast cancer to cause a distinct lump. Instead, ILC may cause a thickening of breast tissue or changes in a nipple.

ILC is sometimes preceded by an uncommon condition called lobular carcinoma in situ (LCIS), marked by abnormal cells confined inside lobules that may be discovered due to a biopsy for other reasons. If you have LCIS, your risk of developing invasive lobular carcinoma in either breast is increased, and you may need extra monitoring by your doctor.

Treatment options for ILC, depending on the individual stage, consist of surgery along with chemotherapy, radiation, and hormone therapy, if appropriate.

Uncommon types of breast cancer

Although fairly rare (accounting for one to five percent of breast cancers), inflammatory breast cancer is very aggressive, according to the National Cancer Institute. That’s why it’s especially important to know the symptoms and act quickly if you notice them. Instead of causing a breast lump, inflammatory breast cancer, which is a sub-type of IDC, blocks lymph vessels in the skin of the breast, resulting in swelling and red inflamed skin.

Inflammatory breast cancer, compared to other types of breast cancer, tends to affect younger women. And they may assume their red rash on a breast is due to an allergy, mastitis, or a skin infection. However, any inflammation of the breast should spark an urgent trip to your doctor. Inflammatory breast cancer spreads rapidly, often in a matter of weeks or months.

Inflammatory breast cancer is treated with a multimodal approach, using systemic chemotherapy to shrink the tumor first, followed by surgery and radiation therapy.

Paget disease of the nipple is also a rare type of cancer. Starting in the breast ducts, this type of breast cancer first spreads to the skin of the nipple and then to the areola (the dark circle around the nipple). The symptoms often look like a benign skin condition such as eczema and can include itching and redness. There may also be a yellow or bloody discharge from a nipple, and the nipple may appear flattened. Many people with this type of breast cancer have one or more tumors in the same breast with skin symptoms.

Breast conserving surgery that includes removal of the nipple and areola, along with radiation therapy, is the best treatment for people with Paget disease of the breast who do not have a breast tumor, according to the National Cancer Institute. If breast tumors are present, a mastectomy is performed along with other treatment, depending on whether there is lymph node involvement.

Phyllodes tumors of the breast can be benign or cancerous. This extremely uncommon type of breast cancer develops in the connective tissue of the breast and, although phyllodes tumors may grow quickly, they rarely spread.

Angiosarcomas begin as cancer cells in blood or lymph vessels. This type of breast cancer usually needs radiation treatment to the breast, according the American Cancer Society. Angiosarcomas may produce skin changes or a lump and tend to grow quickly. Treatment is usually a mastectomy.

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