Breast Cancer: What Should I Know?

Get an overview on what breast cancer is, how it’s diagnosed, and what symptoms to look for.

Not a real patient.

Understanding the facts

What is breast cancer?

Breast cancer is a disease in which cells in the breast grow out of control and form tumors. In most instances, these tumors can be felt as a lump. Type, stage, grade, and hormone receptor status are just a few ways to classify breast cancer.


Type refers to where the cancer has started, along with other factors. The most common breast cancer types are ductal and lobular. Ductal means that the cancer began in the milk ducts. Lobular means that the cancer began in the milk-producing glands. Each of these types has 2 subtypes: in situ and invasive. In situ means that the cancer has not spread. Invasive means that the cancer has spread to nearby tissue in the breast. Below is a list of the most common types and subtypes of breast cancer.

Breast Cancer Types and Subtypes
Ductal carcinoma in situ (DCIS)

About 1 in 5 new breast cancers will be DCIS. This is considered a noninvasive or pre-invasive breast cancer.

Invasive ductal carcinoma (IDC)

This is the most common type of breast cancer and is invasive. IDC starts in the milk duct of the breast, breaks through the wall of the duct, and grows into the fatty tissue of the breast.

Lobular carcinoma in situ (LCIS)

This is considered to be more of a breast change than a breast cancer. The cells that look like cancer cells are growing in the lobules, which are glands in the breast that are responsible for making milk, but they don’t grow through the walls of the lobules.

Invasive lobular carcinoma (ILC)

ILC is an invasive cancer that starts in the lobules and can spread to other parts of the body.


The stage of the cancer refers to how far it has spread from the breast to other parts of the body. Breast cancer is divided into 5 stages. Staging is an important part of the process because accurate staging can help determine treatment.

Stage zero Icon

The changes in the cells are considered precancerous and have not spread to normal breast tissue or the lymph nodes.

Stage One Icon

The cancer is invasive and has spread to normal breast tissue, but not to distant sites.

Stage Two Icon

The cancer is invasive and has spread to nearby lymph nodes, but not to distant sites.

Stage Three Icon

The cancer is considered to be locally advanced, which means that it has spread to nearby tissues or lymph nodes, but not to distant sites.

Stage Four Icon

The cancer can be any size and may or may not have spread to nearby lymph nodes. It has spread to distant organs, such as the bones, liver, brain, or lungs. This stage is also called advanced breast cancer or metastatic breast cancer.

People with metastatic breast cancer and a BRCA mutation have a unique type of cancer. If you have metastatic breast cancer, knowing that you have a BRCA mutation could provide your doctor with helpful information.



Grade is a way to describe the look of cancer cells when compared with healthy cells.

Grade 1:

Cells look more like normal cells and are growing slowly.

Grade 2:

Cells look and act somewhere in between Grade 1 and Grade 3.

Grade 3:

Cells look very different from normal cells and are growing quickly.


During biopsy or surgery, breast cancer cells can be tested to see if they have certain receptors that contribute to cancer growth. The 3 main types of receptors that doctors look at are estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.

Receptor (ER)

ER is a protein found inside of the cell. Estrogen attaches to the ER and this may cause a cell to grow. ER-positive means that the cancer has ERs. ER-positive is also referred to as hormone receptor–positive (HR-positive). If the cancer does not have any ERs, it’s considered ER-negative.

Receptor (PR)

PR is intracellular like ER. PR-positive means that the cancer has PRs. PR-positive is also referred to as HR-positive. If the cancer does not have any PRs, it’s considered PR-negative.

Human Epidermal Growth Factor
Receptor 2 (HER2)

HER2 is a receptor found on the cell surface that normally helps control cell growth. HER2-positive cancer has too much HER2. HER2-negative cancer does not have an excessive amount of HER2.



Breast cancer that is ER-negative, PR-negative, and HER2-negative is called triple-negative breast cancer. This type of breast cancer grows and spreads faster than other types of breast cancer.

Breast cancers that test positive for hormone receptors may receive hormonal therapy. Triple-negative breast cancers do not express ER, PR, or over express HER2, meaning it cannot be treated effectively with hormonal therapy.

BRCA mutations are more common in certain breast cancer subtypes, including triple-negative cancer. However, the majority of breast cancer cases are HR-positive, HER2-negative. So it may come as no surprise that half of the breast cancer cases with BRCA mutations are HR-positive, HER2-negative.

Who can get breast cancer?

Both men and women can get breast cancer, but women are more likely to develop the disease. After skin cancer, breast cancer is the most common cancer in American women. This year alone, almost 300,000 women will learn that they have breast cancer. Certain women may have high risk factors, such as inherited mutations or a family history of breast cancer.

Who can have a BRCA mutation?

Despite what you may have heard, there is no “typical” person with a BRCA mutation. These characteristics alone can’t easily predict your BRCA status:

  • Hormone receptor status
  • Gender
  • Age
  • Ethnicity
  • Family history

Anyone with breast cancer can have a BRCA mutation. Talk to your doctor to see if BRCA testing is right for you.

How is breast cancer diagnosed?

There are several ways to diagnose breast cancer. Mammograms, ultrasounds, and magnetic resonance imaging (MRI) scans are tests that look for breast cancer. If any of these tests show signs of breast cancer, then a breast biopsy is done to confirm whether or not cancer is present.

Can early diagnosis lead to better outcomes?

When breast cancer is found early before it has spread, 99% of women live longer than 5 years after their cancer is diagnosed.

People with a BRCA mutation often experience breast cancer 20 years earlier than those without a mutation (often referred to as early breast cancer).

Finding breast cancer before it spreads (known as metastases) is critical because it's easier to treat successfully.

Signs and symptoms of breast cancer

It’s important to recognize the signs and symptoms of breast cancer. Finding breast cancer early leads to a better chance of successful treatment.

Everybody has a different experience with signs and symptoms. One, some, or none of these may be present for you. Symptoms may include, but are not limited to:

A New Lump or Mass In The Breast

A new lump or mass in the breast

Swelling Of All or Part Of The Breast

Swelling of all or part of the breast

Breast or Nipple Pain

Breast or nipple pain

Nipple Retraction

Nipple retraction

Redness, Scaliness, Or Thickening Of The Nipple Or Breast Skin

Redness, scaliness, or thickening of the nipple or breast skin

Nipple Discharge

Nipple discharge

A New Lump or Swelling in The Lymph Nodes Under The Arm or Near The Collarbone

A new lump or swelling in the lymph nodes under the arm or near the collarbone