Breast Cancer Stages 1-3: A Guide to Diagnosis, Treatment Options, and Life After Treatment

Breast cancer is diagnosed in 1 in 8 women (and 1 in 833 men) at some point in their lifetime. And over 80% of people diagnosed with breast cancer will have stage 1, 2, or 3 (also written as I, II, or III) at the time of diagnosis. It’s easy to feel overwhelmed and confused by all the terms, diagnostic tests, and treatment for the disease. 

In this guide, we will review what these stages mean, common diagnostic tests, and the different types of treatment typically used at these stages. 

Symptoms of breast cancer

Breast cancer does not typically cause any symptoms, especially in the earlier stages. It is more common for it to be first noticed on a screening mammogram. 

If symptoms are present, they may include:

• A lump in the breast, armpit (axilla), or around the collarbone (clavicle)

• Abnormal discharge from the nipple

• Skin changes on the breast, such as redness, dimpling, or a rash

• Changes in breast shape or symmetry

There are many possible explanations for these symptoms other than breast cancer, but typically a new or abnormal mass leads to a mammogram or ultrasound to take a closer look. 

How is breast cancer diagnosed?

The diagnosis of breast cancer is a multistep process, and the process can vary from person to person. But the diagnostic workup commonly looks something like this:

• A screening mammogram may show an area of concern, or a physical examination may reveal a breast lump that needs more evaluation.

• If a “screening” mammogram spots an abnormality, this is usually followed by a more detailed “diagnostic” mammogram. This second test takes a much closer look at the suspicious area. It also typically includes an ultrasound, which takes a look at nearby lymph nodes to look for any signs of cancer. 

• If there is a question of cancer, a biopsy is performed. This procedure collects a sample of cells from the abnormal area seen on the mammogram. A specialist, called a pathologist, then looks at the cells under a microscope to determine if they are cancerous. 

• If the biopsy confirms a diagnosis of breast cancer, most people will then see a cancer specialist. This could be a breast surgeon or a breast oncologist (another word for cancer specialist). This doctor will get you started on the next steps to treat the breast cancer. 

In addition to the testing above, more tests are done on the cancer cells from the biopsy sample. The cells are tested for certain characteristics, such as:

• Hormone receptor status: Breast cancer cells, like normal breast cells, may have certain receptors on their surface that make them grow in response to estrogen. These include estrogen receptors (ER) and progesterone receptors (PR). Breast cancers may be receptor-positive, meaning the receptors are present, or receptor-negative, meaning the receptors are negative. 

• Human epidermal growth factor receptor 2 (HER2) status: The HER2 receptor is usually present in small quantities on normal breast cells. When high levels of this receptor are present, they may contribute to cancer growth. So, breast cancer cells are also labeled as HER2-positive (high levels of receptor) or HER2-negative (low levels of receptor).

Breast cancer cells can have any combination of the receptors or none at all. Triple-negative breast cancer refers to cancer that has no hormone receptors and normal levels of HER2. The receptor status is important in breast cancer staging and treatment, as we’ll discuss in the sections below. 

How is breast cancer staged?

Breast cancer staging is a way of classifying how far a tumor has advanced. It takes into account several different characteristics of the tumor. 

Some of these characteristics include:

• The type of breast cancer (in other words, the specific type of breast cells that initially became cancerous)

• The size of the tumor

• If the tumor has invaded nearby or distant tissues

• Lymph-node involvement 

• Receptor status

Another important consideration in staging is the grade of the cancer cells. Higher grades generally mean that the cancer cells might appear more abnormal, or divide at a faster rate. Grade is determined by the way the cancer cells appear under the microscope. 

Staging is a complicated process, and oncologists use multiple different staging strategies. “Anatomic staging” is often the first and most commonly used system. It stages the cancer based on size and spread, before taking into account factors like receptor status and cancer grade. It’s based on something called the TNM system:

• T describes the size of the tumor

• N reflects the number and location of lymph nodes involved

• M refers to the presence or absence of metastasis (spread to distant organs) 

This guide focuses on defining breast cancer stages by the anatomic TNM system, given this is the most commonly used staging system. 

What defines breast cancer stages 1, 2, and 3?

Stages 1, 2, and 3 all mean the cancer has not spread beyond nearby areas like lymph nodes or the tissue of the chest wall. In other words, the cancer has not spread to distant parts of the body (metastasized). 

Breast cancer cannot be officially staged until after surgery. Diagnostic tests, like a mammogram and ultrasound, can help to estimate the likely stage before surgery. But once the tumor is removed, your specialist will have a lot more information. Surgery will help determine the exact size of the tumor, if it has spread into nearby tissues, and whether lymph nodes are involved.   

Stage 1 breast cancer

Stage 1 breast cancer means the breast tumor has just started to invade nearby, non-breast tissue. 

Stage 1 is divided into two categories.

Stage 1A means the tumor size is 20 millimeters (0.78 inches) or less, and there is no lymph node involvement.

Stage 1B means the tumor size is also 20 millimeters (0.78 inches) or less. But in this stage, there is something called micrometastasis. This means that a small amount of cancer cells have spread to the lymph nodes. These cells cannot be detected on imaging studies. This is why a sample of lymph nodes are removed during surgery, so they can then be checked for cancer.  

Stage 2 breast cancer

In stage 2 breast cancer, there is spread to local areas and possibly nearby lymph nodes. 

Similar to stage 1, stage 2 is further divided into two categories.

Stage 2A includes two possible scenarios:

• The tumor is 20 millimeters (0.78 inches) or less, and the cancer has spread to a few of the lymph nodes in the armpit (also referred to as the axilla). 

• The tumor is larger — between 20 and 50 millimeters (0.78 to 1.9 inches) — but there is no lymph node spread detected.

Stage 2B also includes two possible scenarios:

• A larger tumor — between 20 and 50 millimeters (0.78 to 1.9 inches) — with spread to a few axillary lymph nodes.

• A tumor over 50 millimeters (1.9 inches) in size, but there is no spread to nearby lymph nodes and no spread to the chest wall or skin. 

Stage 3 breast cancer

Stage 3 breast cancer is also known as locally advanced breast cancer. It’s divided into three stages and also includes rare “inflammatory” breast cancers.

Stage 3A includes:

• A tumor size of 50 millimeters (1.9 inches) or less, with spread to a group of axillary lymph nodes that are stuck together (matted) or immovable. This suggests there is significant lymph node involvement.

• A tumor larger than 50 millimeters (1.9 inches) but that has spread to only a few axillary lymph nodes. 

Stage 3B refers to a tumor of any size that has spread to the chest wall or skin. Lymph node involvement is absent or minimal.

Stage 3C can also include a tumor of any size, but there is extensive lymph node spread. This can include affected lymph nodes in the armpit (axilla), chest, or near the collarbone (clavicle). 

Inflammatory breast cancer 

This is a rare form of breast cancer which only affects 2-4% of all people diagnosed with the disease. Inflammatory breast cancer is automatically staged as stage 3B or higher because it involves the skin. It typically produces noticeable skin changes as it develops, such as redness and swelling that starts in one area and extends to the entire breast over time.

Treatment of breast cancer stages 1-3

The goal of treatment for breast cancer stages 1-3 is to cure the cancer. A brief overview of treatment options is discussed below. These are broadly divided into two main categories:

1) Localized therapy includes surgery, with or without radiation. This type of treatment directly addresses the breast tumor. Surgery removes the tumor, and radiation kills any cells that may have been left behind after the tumor is removed. 

2) Systemic therapy includes chemotherapy, endocrine (hormone) therapy, targeted therapy, and immunotherapy. Systemic therapy works by delivering medicine to the whole body, to kill any undetectable cancer cells that may be wandering around in the bloodstream or lymphatic system.  

Most treatment plans for stages 1-3 involve a combination of localized and systemic therapy. This means that most people will be treated with a combination of surgery, radiation, and one or more types of systemic therapy. But the specific types of treatment, and the order in which these treatments are given, depends on the individual. 

Localized therapy

The goal of localized therapy is to remove or kill the original tumor and stop any cancer cells from traveling to other areas of the body. The main type of localized treatment is surgery, but radiation falls under this category, too. 

Surgery for breast cancer can involve a few different approaches: 

• A lumpectomy, or partial mastectomy, removes the tumor and some of the surrounding breast tissue. This approach is used to spare healthy breast tissue. This is an option if the tumor is well contained and doesn’t take up a large part of the breast.

• A mastectomy removes the entire breast and is better for larger or more spread-out tumors.

• Either of these procedures may be paired with a removal of lymph nodes, as well. A surgeon might remove just a few lymph nodes, so they can be checked for cancer spread. But a larger sampling of lymph nodes may be removed if there is known lymph node involvement at the time of surgery. In some people with breast cancer that has a low risk of spread, lymph nodes may not need to be removed.

Surgery is often followed by radiation treatment, which is performed by a radiation oncologist. This treatment kills any cancer cells that were left behind after surgery. 

Systemic therapy

Systemic therapy refers to medications that are designed to reach the whole body rather than just the specific location of a known tumor. This treatment not only kills the cancer cells in a tumor, but also catches any cells that may have escaped the main tumor and formed micrometastases. These are cancer cells that are impossible to detect by imaging or lab tests because they are too small in number. 

It is common for several different types of systemic therapies to be used together for treatment. 

Different types of systemic therapy include:

• Chemotherapy kills cells that divide rapidly, like cancer cells. It works best on more aggressive cancers because it has the greatest effect on cells that are multiplying more rapidly. Chemotherapy is typically given through an intravenous (IV) infusion. 

• Hormone therapy is used for hormone receptor-positive breast cancer. It blocks estrogen from connecting to these receptors, which, in turn, slows down cancer growth. It includes hormone receptor blockers like selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs).

• Targeted therapy is used in HER2-positive breast cancer. Similar to hormone therapy, it blocks these receptors to slow cancer growth.

• Immunotherapy includes medications that help the body’s immune system to kill cancer cells. It may cause side effects by causing the immune system to attack the body’s normal cells as well, leading to autoimmunity.

Sometimes, systemic therapy will be started before surgery — especially for people with HER2+ or triple-negative breast cancer. This is called neoadjuvant therapy. This approach can provide important feedback about which type of systemic therapy is best for a specific cancer. By observing the way a tumor responds to a specific chemotherapy drug before it is surgically removed, oncologists know which drugs to use after surgery (called adjuvant therapy).

Treatment decisions are complex and differ for each individual person. If you have been diagnosed with breast cancer, know that you will have a team of healthcare providers and specialists to help you develop a treatment plan that is right for you. 

What steps can I take to help prevent recurrence after treatment?

After treatment, many people diagnosed with stage 1, 2, or 3 breast cancer will live the rest of their life cancer-free. But recurrence can happen. The good news is that there are steps you can take to help prevent recurrence, or catch it if it happens. 

The first step in avoiding recurrence is regular follow up with your oncologist. Initially, you may see your healthcare provider several times per year. Over time, these visits may be more spread out as you remain cancer-free. This includes regular mammograms, which are recommended for people who did not have a total mastectomy. And mammograms should also continue for the unaffected breast.

If your breast cancer was hormone receptor-positive, another important step to help prevent recurrence is taking hormone therapy. These medications are sometimes taken for 5 to 10 years after breast cancer treatment is completed.  

In addition to regular screening and hormone therapy, there are also risk factors for recurrence that we can control. These are called modifiable risk factors. 

It’s helpful to avoid or minimize:

• Hormonal medications, such as birth control pills, or hormone replacement therapy 

• Heavy alcohol use

• Smoking (its relationship to breast cancer is not fully understood, but studies suggest it may be associated with increased risk)

• Foods high in saturated fats

• Increased body weight or obesity

• Decreased physical activity

LIfestyle changes that address modifiable risk factors are a powerful way to help prevent the recurrence of breast cancer. And surrounding yourself with a good support system — close friends, family, your healthcare providers, or even a survivor support group — can help you manage any anxiety you might feel regarding cancer recurrence.

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Written by:

Joanna Jan, MD

Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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