Stage 3 breast cancer

This page was reviewed under our medical and editorial policy by

Daniel Liu, MD, Plastic and Reconstructive Surgeon

This page was updated on September 20, 2022.

In stage 3 breast cancer, also called invasive breast cancer, abnormal cells are growing in the breast and other nearby tissues, such as the muscles of the chest and lymph nodes. Tumors are typically larger than those in stage 1 or 2, but the cancer has not spread to other parts of the body.

What are the stages of stage 3 breast cancer?

Your care team will determine breast cancer stage based on many factors, starting with a system called TNM:

  • T is for the tumor size 
  • N is for the number of lymph nodes affected
  • M is whether it has metastasized, or spread to other parts of the body, which is not the case with stage 3 breast cancer

Lymph nodes are small pockets of tissue that filter a clear fluid called lymph. They’re key points along the lymphatic system, which runs throughout the body. The lymphatic system is one route that cancer takes to spread.

Both tumor size and the number and location of affected lymph nodes are used to determine whether stage 3 breast cancer is stage 3A, 3B or 3C. Testing will determine whether cancer is detected in four key areas of lymph nodes:

  • Axillary lymph nodes, which are around the armpit
  • Lymph nodes by the breastbone (in the center of the chest)
  • Lymph nodes under the collarbone
  • Lymph nodes above the collarbone

Stage 3A breast cancer

Stage 3A breast cancer is characterized in one of the following ways:

  • A breast tumor of any size with cancer found in four to nine lymph nodes in the armpit or cancer that has spread to lymph nodes near the breastbone.
  • The primary tumor in the breast is larger than 5 cm and cancer has spread to between one and three armpit lymph nodes.

Stage 3B breast cancer

Stage 3B breast cancer is characterized in one of the following ways:

  • The cancer has spread to the chest wall.
  • The cancer has been diagnosed as inflammatory breast cancer.
  • The cancer may also be in up to nine lymph nodes in the armpit or those near the breastbone.

Stage 3C breast cancer

In stage 3C breast cancer, the cancer has spread to 10 or more lymph nodes in the armpit, below the collarbone and near the breastbone. The cancer may also have spread to the chest wall, may have been diagnosed as inflammatory breast cancer, or both.

Stage 3 breast cancer grading and other information

The analysis of tumor and lymph node tissue samples in a lab helps determine the cancer’s grade, or how abnormal the cancer cells look in comparison to healthy, normal cells. A pathologist will look at how cells are dividing to determine:

  • The cancer’s growth rate
  • How much of the tissue has normal-looking milk ducts
  • How many nuclei each of the tumor cells have (nuclei contain genetic information for the cells)

The cancer is then given a grade from G1 to G3.

G1 is a lower grade indicating the cells look more normal. G3 is a higher grade indicating the cells look more abnormal than healthy cells. Higher-grade cells grow faster and spread more quickly.

Tests on tumor samples also analyze the genetics of the cancer cells and their molecular characteristics. Knowing the type of hormone receptors on the cancer cells will help guide treatment:

HER2-positive breast cancers make too much of the human epidermal growth factor 2 protein. This helps the cancer grow.

ER-positive breast cancers have estrogen receptors on their surface. The tumors grow when exposed to estrogen.

PR-positive breast cancers have progesterone receptors on their surface. These tumors grow when exposed to progesterone.

Triple-negative breast cancers do not have any of the above hormone receptors on their surfaces. These cancers are harder to treat.

Stage 3 breast cancer symptoms

Symptoms with stage 3 breast cancer may include:

  • Changes to the skin of the breast, including dimpling, redness or other color changes, scaliness or open sores
  • A lump or swelling in the breast or armpit
  • Nipple changes, such as a discharge (which can be clear or opaque, red, yellow or green), peeling or flaking, or an inverted or flattened nipple
  • Changes to the size or shape of the breast
  • Pain, irritation or itchiness
  • Breasts that are red, warm to the touch or swollen

Stage 3 breast cancer treatment

Treatment for stage 3 breast cancer typically involves surgery, radiation, chemotherapy and other specific therapies, with the order of these treatments tailored to each patient.

For many people, treatment will start with chemotherapy, drugs that work throughout the body to kill cancer cells. The goal of having chemotherapy before surgery, an approach called neoadjuvant therapy, is to shrink the tumor and decrease the amount of cancer that’s spreading in the body. Though chemotherapy’s mission is to destroy cancer cells, it also tends to harm normal cells that are dividing and fast-growing, causing specific side effects. For instance, damage to cells in the lining of the digestive tract may cause nausea, diarrhea and mouth sores. When hair follicles are affected, hair stops growing and falls out.

Depending on the specific characteristics of the tumor, the patient may also get targeted therapies before surgery. These drugs specifically target characteristics of cancer cells, such as proteins they produce or pathways they use to grow or evade the body’s defenses. For instance, HER2-positive tumors are typically treated with the targeted drugs Herceptin® (trastuzumab) and Perjeta® (pertuzumab).

After neoadjuvant therapies, the patient undergoes surgery to remove the breast cancer tumor. This procedure typically involves a mastectomy, which removes the entire breast. Sometimes, neoadjuvant therapy works well enough that breast-conserving surgery is possible. The surgeon will typically remove axillary lymph nodes at the same time as surgery.

Patients typically undergo radiation treatment after surgery to target cancer cells that may have been left behind. Depending on the specific characteristics of a person’s stage 3 breast cancer, the doctor may recommend more chemotherapy, targeted therapies and/or hormone therapies afterward. Patients may take specific drugs for one or more years to help reduce the likelihood of cancer recurring.

Stage 3 breast cancer survival rate

The survival rate for stage 3A breast cancer may be slightly higher than for stage 3B, and the survival rate for stage 3B may be slightly higher than for stage 3C. However, all women diagnosed with stage 3 breast cancer have several promising treatment options.

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