What to Know About the Types of Breast Cancer

There are many different types of breast cancer, and if you or a loved one has recently been diagnosed, it can be helpful to know and understand the differences. According to the American Cancer Society, the terms used for types of breast cancer represent the specific cells in the breast that are affected with the cancer.

Though breast cancer originates in the breast, it can spread to surrounding tissue or to lymph nodes. It can also spread to more distant organs, like the liver or bones. Cancer is when cells grow out of control and can form a tumor. Often, breast cancer lumps are either felt during an exam (a self-exam by the patient or a breast exam given by her doctor) or seen on an X-ray, like a mammogram or CT scan. While many women may be alarmed when a lump is discovered, it’s important to note that most breast lumps are not cancerous. To be sure, talk to your doctor if you find a lump so it that it can be tested. If it is found to be malignant, it’s called breast cancer.

The American Cancer Society notes that the most common breast cancers include ductal carcinoma in situ (DCIS) and invasive carcinoma. Others, like phyllodes tumors and angiosarcoma, are less common. There are also changes that can occur in a breast that aren’t cancer themselves, but increase your risk for getting breast cancer later on, like lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia.

In situ vs. invasive breast cancers

In addition to describing the specific cells in the breast that are affected by cancer, the type of breast cancer can also describe whether the cancer has spread. For example, "in situ" breast cancer (as in ductal carcinoma in situ, or DCIS) is a cancer that starts in a milk duct and has not grown into the rest of the breast tissue. The term “invasive breast cancer” is used to describe any type of breast cancer that has spread into the surrounding breast tissue.

Ductal carcinoma in situ

It's estimated that one in five new breast cancer diagnoses is for DCIS. The good news is that this early stage of breast cancer can be cured, the American Cancer Society says. It’s called stage 0 cancer.

DCIS is a non-invasive or pre-invasive breast cancer, meaning that although the cells that line the ducts are now cancer cells, they are contained so they have not spread to the walls of the ducts or the breast tissue.

It’s important to know, however, that DCIS can become invasive cancer — meaning that the cancer spreads to nearby tissue and metastasizes to other parts of the body. The challenge is that there’s no way to know for sure which DCIS breast cancers will become invasive cancer and which will not. As a result, almost everyone with DCIS will be treated so that the cancer does not spread.

Treatment of DCIS often involves breast-conserving surgery, commonly known as a lumpectomy, the American Cancer Society says. This surgery involves removing the cancer — and in some cases the surrounding lymph nodes and healthy tissue — but leaving as much of the breast as possible. In some cases, a mastectomy is needed, meaning removal of the complete breast tissue.

Lobular carcinoma in situ

With LCIS unusual cells grow in the lining of a milk gland, or lobule. They don’t advance beyond the gland and the cells themselves aren’t cancerous. Because LCIS doesn’t cause a lump and the cells aren’t visible on a mammogram, it will go unnoticed, only to be discovered if you have a biopsy for another reason. The concern over LCIS comes from the fact that having these cell changes increases the risk for breast cancer by 7 to 12 times, reports the American Cancer Society. Still, there’s disagreement about whether LCIS should be called a carcinoma or be considered a pre-cancer because LCIS cells don’t turn cancerous and, should breast cancer occur, it’s just as likely to be in the opposite breast from where the LCIS was found. In fact, LCIS is sometimes called lobular neoplasia, meaning simply an abnormal growth in the lobule.

Invasive breast cancer

Invasive breast cancer is more serious because the cancer has spread into surrounding breast tissue. The most common types of invasive cancer are invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC). Invasive ductal carcinoma makes up about 70 to 80 percent of all breast cancers.

Also within the category of invasive breast cancer is triple-negative breast cancer, which is a very aggressive breast cancer that accounts for about 15 percent of all breast cancers. It is a difficult cancer to treat.

A rare type of invasive breast cancer is inflammatory breast cancer, which accounts for about 1 to 5 percent of all breast cancers. Another rare form is Paget disease of the breast — a cancer that starts in the breast ducts and spreads to the skin of the nipple and then to the areola (which is the dark circle around the nipple). Paget disease accounts for only about 1 to 3 percent of all cases of breast cancer. Another rare form of breast cancer is known as a phyllodes tumor, which develops in the connective tissue (stroma) of the breast. One of the rarest types of breast cancer is a form of sarcoma. Angiosarcoma starts in cells that line blood vessels or lymph vessels.

Surviving breast cancer

The survival rate for breast cancer varies by the type of breast cancer a woman has and the stage of the breast cancer. The National Cancer Institute’s Surveillance, Epidemiology and End Results program (SEER) collects cancer data across the country and from it compiles national cancer statistics, including a five-year breast cancer survival rate based on SEER data.

Currently, the percentage of breast cancer patients expected to live at least five years after being diagnosed, according to SEER data, is:

• For stage 1 breast cancer, 98 to 100 percent
• For stage 2 breast cancer, 90 to 99 percent
• For stage 3 breast cancer, 66 to 98 percent

Additionally, SEER data indicates an expected five-year survival rate based on staging category (meaning how much the cancer has spread) at the time of diagnosis.

• Localized, meaning the cancer cells have not spread beyond the breast: 99 percent
• Regionalized, when the cancer has spread beyond the breast, possibly to the lymph nodes or nearby tissue, but the spread is limited to that region: 86 percent
• Distant, which is the most serious form of breast cancer, when the cancer has spread to other parts of the body (what is called metastasis): 27 percent

Breast cancer recurrence

The good news, according to Johns Hopkins Medicine, is that most breast cancer patients will not experience a recurrence of their disease. But if it does happen, breast cancer recurrence can be treated most of the time, and cured some of the time.

The key factors that affect the risk for recurrence include the type and location of the original breast cancer. It’s important to closely monitor your health and promptly report any changes if you have breast cancer because the highest risk for recurrence is during the first two years after treatment.

Certain lifestyle changes may reduce the chances of your cancer returning. These include:

• Exercising daily and eating a healthy diet
• Keeping your weight in check
• Taking care of yourself emotionally by limiting stress, being actively involved in your health and joining a support group so you don’t feel alone
• Limiting alcohol consumption
• Getting regular screenings (mammograms)

Screening and risk reduction

Though some women may experience symptoms of breast cancer, including pain or an inverted nipple, many women diagnosed with breast cancer have no symptoms. That's why screening is so important, the American Cancer Society says.

Screening includes doing regular breast exams at home, having clinical breast exams by your doctor and getting regular mammograms. If your doctor finds something on a mammogram, he or she may send you for more tests, including possibly a breast ultrasound or a breast MRI. If cancer is suspected, your doctor may recommend a biopsy. That's the only way to know for sure if it’s cancer.

Having regular screening tests and staying healthy by keeping your weight in check, exercising regularly and eating a healthy diet are good lifestyle choices. Also speak to your doctor about whether you might be eligible to take a hormonal modification pill, such as tamoxifen, to reduce your risk for breast cancer. This could be especially important if you have LCIS because of your higher risk for breast cancer later on. While there are some risk factors you can’t change — like family history and genes — other risk factors, such as alcohol consumption, are within your control. The American Cancer Society notes that drinking alcohol has been linked to an increase risk for breast cancer.

Staying diligent about your health and making it a priority is an important first step in fighting breast cancer.