What To Know About the Breast Cancer Stages

Breast cancer is a type of cancer that starts growing in the breast tissue.1 Healthcare providers classify breast cancer into five stages, stage 0 to stage 4. The stage indicates how advanced the cancer is depending on several factors, such as the size of the tumor and the extent the cancer has spread. Stage 0 is the earliest, and stage 4 is the most advanced.

Understanding your cancer stage helps your healthcare team determine the ideal treatment plan and predict the outlook of your cancer.

How Is Breast Cancer Stage Determined?

After your healthcare provider has diagnosed breast cancer, they will typically do tests to determine the cancer stage. These tests include:

• Physical examination: This may involve examining your breast and surrounding areas as well as asking questions about your personal and family medical history.
• Imaging tests: Tests—such as X-rays, computerized tomography (CT) scans, magnetic resonance imaging (MRI), positron emission tomography (PET) scans, and ultrasounds—can help give more information about your cancer and whether it may have spread in your body.
• Blood tests: Your healthcare provider may order blood tests to check for specific proteins and the function of organs such as your liver.
• Biopsy: Different forms of breast biopsy, such as the sentinel lymph node biopsy (SLNB), may also be helpful. The SLNB involves removing a sample from the sentinel lymph node—which is the first lymph node (a small organ that's part of your immune system) the cancer is likely to spread to—and examining it under a microscope to look for cancer cells.5 Healthcare providers may also test a biopsy for the presence, absence, or amount of hormone receptor proteins and human epidermal growth factor receptor 2 (HER2) proteins.

The TNM Staging System

The American Joint Committee on Cancer (AJCC), a team of cancer experts who oversee how cancer is classified, created the TNM staging system that most healthcare providers use to stage cancer. This system involves:8

• T staging categories: The T categories consider the size of the primary tumor. They are designated by numbers 0-4, depending on tumor size and whether it has spread to the chest wall, skin, or underneath the breast.
• N staging categories: This category, which uses numbers 0-3, explains if and how much cancer has spread to nearby lymph nodes.
• M staging categories: This factor assesses whether and how much the cancer has spread (metastasized) to areas and organs farther from the breast tissue (distant organs), such as your liver and bones.

An update to the AJCC’s staging system means the TNM system also now assesses:

• Hormone receptor status: Whether or not the cancer cells have proteins called estrogen receptors or progesterone receptors
• HER2 status: How much HER2 protein the tumor makes
• Grade: How much the cancer cells look like normal cells

Oncologists, or doctors specializing in diagnosing and treating cancer, use the information in the TNM staging system to determine a stage 0-4. Because it considers so many factors, staging breast cancer is a complex process. It's best to speak with your healthcare team to understand your cancer stage.

Below is a table that summarizes these stages of breast cancer and what they may mean.

Stage 0 Breast Cancer

Cancer at this stage is noninvasive, meaning it is only within cells that line the breast ducts or lobules. Stage 0 breast cancer is also known ductal carcinoma in situ (DCIS).10 In-situ disease usually can't spread to the lymph nodes or other areas like invasive cancer can.

Symptoms: You may not have any noticeable symptoms with stage 0 cancer, but you may have abnormal findings on a mammogram.

Treatment: Your healthcare provider may recommend breast-conserving surgery (a partial mastectomy, in which a part of the breast rather than all of the breast tissue is removed). You may also need radiation in some cases.

Outlook: DCIS is very treatable, and nearly everyone with this early-stage cancer can be cured with treatment.

Stage 1 Breast Cancer

Stage 1 breast cancer is divided into substages:

• 1A: Tumors have not spread outside the breast but measure up to 2 centimeters. 
• 1B: The tumor is less than 2 centimeters but has spread to the nearby lymph nodes in small groups.

Tumors that meet the condition of stage 1B may still be classified as stage 1A if hormone receptor proteins are present because these proteins make the cancer less aggressive.

Symptoms: Cancer at this stage may or may not cause symptoms. Symptoms that may occur include:

• Lumps in your breast
• Nipple discharge
• Skin dimpling
• Inverted nipple (the nipple goes inward)

Treatment: Surgery to remove the cancer is the go-to treatment for stage 1 breast cancer. Healthcare providers sometimes also recommend chemotherapy and hormone therapy.

Outlook: Stage 1 breast cancer is also considered early-stage, localized cancer (the cancer hasn't spread outside of the tissue where it began except for to nearby nodes). Localized breast cancers have a five-year relative survival rate of nearly 100%—meaning people who have it are, on average, nearly 100% as likely as those without it to live for at least five years after diagnosis.

Stage 2 Breast Cancer

The subcategories of this invasive breast cancer include:

• Stage 2A: There's a tumor larger than 2 centimeters (but less than 5 centimeters) in the breast tissue that has not spread to the lymph nodes. Less commonly, this stage means there's no tumor in the breast, but smaller ones appear in lymph nodes in the underarm or by the breast bone.
• Stage 2B: The tumor is larger than 2 centimeters but less than 5 centimeters and has spread to nearby lymph nodes, or the tumor is larger than 5 centimeters but with no lymph node involvement.

Symptoms: Stage 2 breast cancer may cause similar breast symptoms as stage 1 cancer.

Treatment: Treatment for stage 2 breast cancer typically involves the use of medications (chemotherapy and other drugs) and surgery to remove part or all of the breast, followed by radiation therapy.1916 The goal is to cure the cancer.

Outlook: The five-year survival rate after treatment is about 93%.

Stage 3 Breast Cancer

Stage 3 breast cancer is invasive. It's divided into these subcategories:

• Stage 3A: The breast tumor is larger than 5 centimeters and has spread to one to three lymph nodes, or the tumor is any size and has spread to four to nine lymph nodes.
• Stage 3B: Cancer has spread to the chest wall and may be found in up to nine lymph nodes.
• Stage 3C: The tumor is any size and has spread to the skin of the breast, chest wall, and 10 or more lymph nodes.

Symptoms: You're more likely to have symptoms in stage 3 than earlier stages. Symptoms affect the breast and may include:

• A lump
• Skin texture changes, including dimpling or scaliness
• Open sores
• Itchiness
• Swelling
• Nipple discharge

Treatment: Healthcare providers also aim for a cure when treating stage 3 breast cancer. They may recommend chemotherapy to help shrink the tumor before doing surgery. You may also need radiation therapy and additional medication after surgery.

Outlook: While treatment is more challenging at this stage, the five-year relative survival is about 75%.1920

Stage 4 Breast Cancer

This is also known as metastatic breast cancer. Cancer at this stage has spread to organs and parts of the body farther away from the breast.

Symptoms: Stage 4 breast cancer symptoms vary depending on where the cancer has spread. For instance, cancer that has spread to the bones may cause fractures and pain. Cancer in the lungs may cause shortness of breath and difficulty breathing. Cancer in the brain may cause headaches and seizures. Cancer that has spread to the liver may cause jaundice, which is yellowing of the skin or white areas of the eyes.

Treatment: This stage of breast cancer is considered incurable. However, treatments may help improve symptoms, slow cancer growth, and help you live longer.

Outlook: The five-year survival rate is about 32%.

Preventing or Slowing Progression

Cancer may sometimes progress to a more advanced stage, especially if you don't treat it. How breast cancer may progress from one stage to another can also vary depending on factors like the activity of hormone receptor proteins and your family history of breast cancer.

Still, feeling empowered to control what's in your control is important. Strategies that may be helpful in preventing or slowing down the progression of your cancer include:

• Reach and maintain a weight that you and your provider decided is optimal for you.
• Opt for a diet rich in fruits, vegetables, fish, lean protein, and whole grains instead of processed and ultra-processed foods like cakes, sausages, and sweetened beverages.
• Be physically active. You can speak with your healthcare provider about safe exercises for you and their intensity.
• Avoid alcohol. Evidence suggests its consumption increases the risk of developing breast cancer in the first place.
• Quit cigarette smoking, which has been linked to increased risk of death with breast cancer.
• Speak with your healthcare provider about dietary supplements that may help, such as vitamin D.

Restaging

Sometimes, breast cancer may be staged again after the initial staging.Your healthcare provider may suggest restaging your cancer if it worsens or recurs or to check how it has responded to treatment. Restaging uses the same tests your healthcare provider used to initially stage the cancer.

Restaging can help healthcare providers understand your current health and guide future treatments, but the new stage classification doesn’t replace the initial stage. The initial stage remains the most important when discussing statistics such as survival rates. The new stage may indicate your prognosis (outlook), though.

Life Through the Stages

Living with any stage of breast cancer can be challenging, as the different stages often require various forms of treatment that may come with unwanted side effects.1630 It's important to talk to your healthcare provider about any side effects you experience so they can help you manage them.

Depending on your breast cancer stage, you may want to consider enrolling in a clinical trial to try out new treatments. This may be particularly beneficial for people with stage 4 breast cancer, which is less treatable with current therapies. You can speak with your healthcare provider about eligibility and recommendations or search for trials on databases like ClinicalTrials.gov.

Having a support system in addition to your healthcare team can be helpful in navigating breast cancer. A strong support system may include family, friends, and a support group made up of others who have been diagnosed with breast cancer. 

A Quick Review

If you've received a breast cancer diagnosis, your healthcare team will follow up with tests to determine the stage. The five stages of breast cancer, stages 0-4, help describe how advanced the cancer is and what treatment plan may be most effective.

Healthcare providers most commonly use the TNM system to stage cancer. This system categorizes breast cancer into different stages using key factors like tumor size, spread of disease, lymph node involvement, and the presence of specific biomarkers.

Source: Health.com