Breast Cancer Stage III

Stage 3 breast cancer, also called locally advanced breast cancer, means the cancer has spread beyond the breast tissue to nearby lymph nodes or surrounding structures, but has not reached distant parts of the body.

Table of contents

• What is Stage 3 Breast Cancer?
• Understanding the Substages: 3A, 3B, and 3C
• Signs and Symptoms
• TNM Staging System
• Treatment Approaches

What is Stage 3 Breast Cancer?

Stage 3 breast cancer is a more advanced form of the disease than stages 1 and 2. At this stage, the cancer has spread from the breast to nearby areas, but it has not been found in distant sites in the body^[1]. This type of breast cancer is also known as locally advanced breast cancer, which means the cancer has grown beyond the original breast tissue into nearby structures^[2].

The stage of a cancer tells doctors how big it is and how far it has spread. This information helps your medical team decide the best treatment approach for you^[2]. Stage 3 breast cancer has one or more of the following features: the tumor may be large, typically bigger than 5 centimeters; it may have spread to several lymph nodes in the underarm area or other areas near the breast; or it may have spread to other tissues around the breast such as skin, muscle, or ribs^[5].

It’s important to know that staging for breast cancer is very complex. Many different factors are considered before doctors can confirm your final stage^[2]. If you have any questions about your staging, speak to your doctor or breast cancer nurse specialist.

Understanding the Substages: 3A, 3B, and 3C

Stage 3 breast cancer can be divided into three substages: 3A, 3B, and 3C. Each substage describes different patterns of cancer spread.

Stage 3A means one of the following situations: either no cancer is seen in the breast or the cancer is of any size within the breast, and there is cancer in 4 to 9 lymph nodes under the arm or in lymph nodes near the breastbone. Stage 3A can also mean the cancer is larger than 5 centimeters and has spread to 1 to 3 lymph nodes under the arm or to the lymph nodes near the breastbone^[2].

Stage 3B means the cancer has spread to the skin of the breast or the chest wall. The chest wall means the structures surrounding and protecting the lungs, such as the ribs, muscles, skin, or connective tissues (tissues that support and connect different parts of the body). The cancer has made the skin break down, creating an ulcer (an open sore), or caused swelling. The cancer may have spread to up to 9 lymph nodes in the armpit or to the lymph nodes near the breastbone^[2]. Cancer that has spread to the skin of the breast might be an inflammatory breast cancer, a rare and aggressive type of breast cancer^[2].

Stage 3C means the cancer can be any size, or there may be no cancer seen in the breast. The cancer may have grown into the chest wall or skin of the breast. The cancer has spread to one of the following: 10 or more lymph nodes in the armpit; lymph nodes above or below the collar bone; or lymph nodes in the armpit and near the breastbone^[2].

Signs and Symptoms

Signs of locally advanced breast cancer may include several visible or physical changes. You might notice thickened skin which may look dimpled like an orange peel. There may be ulcerated skin on the breast, which means the skin has broken down. You may find a lump in the breast which feels attached to the chest wall and doesn’t move freely^[5].

Other symptoms can include a large red, swollen breast, which is called inflammatory breast cancer. You might also notice a large lump in the armpit that may not move freely from the chest wall, or a lump at the base of the neck^[5].

TNM Staging System

TNM stands for Tumor, Node, and Metastasis. This is another system doctors use to describe breast cancer. The T describes the size of the tumor, the N describes whether there are any cancer cells in the nearby lymph nodes, and the M describes whether the cancer has spread to parts of the body further away from where the cancer started^[2].

The doctor gives each factor a number. The number depends on how far the cancer has grown or spread. For example, a very small cancer which hasn’t spread to the lymph nodes or elsewhere in the body may be T1 N0 M0. A larger cancer that has spread into the nearby lymph nodes and to another part of the body may be T3 N1 M1^[2].

In the TNM staging system, stage 3A breast cancer is the same as: T0 N2 M0, T1 N2 M0, T2 N2 M0, T3 N1 M0, or T3 N2 M0. Stage 3B is the same as: T4 N0 M0, T4 N1 M0, or T4 N2 M0. Stage 3C is the same as: any T with N3 M0^[2].

Treatment Approaches

The number staging helps your doctor decide which treatment you need. Treatment also depends on the type of cells the cancer started in, whether your cancer cells have receptors for particular cancer drugs, the grade of the cancer, whether you have had the menopause, and other health conditions you may have^[2]. Your doctor will take many different factors into account when deciding which treatment is best for you.

A combination of different treatments often works best for stage 3 breast cancer^[11]. You might have drug treatments such as chemotherapy (medicines that kill cancer cells) with or without a targeted cancer drug (medicines designed to target specific features of cancer cells) as a first treatment. This is followed by surgery and then radiotherapy (treatment using high-energy rays to destroy cancer cells) or more drug treatments^[2].

Alternatively, you might have surgery as a first treatment followed by radiotherapy, chemotherapy, or other drug treatments^[2]. Chemotherapy is a common treatment for stage 3 breast cancer. Sometimes people have chemotherapy before surgery to shrink a tumor and make it easier to remove. It can help destroy cancer cells that remain after surgery. In cases where surgery isn’t an option, chemotherapy may be the main treatment^[11].

You might have chemotherapy as the first treatment to shrink the cancer. Or you might have hormone therapy first if your cancer cells have hormone receptors and it’s not suitable for chemotherapy. If your cancer cells have HER2 receptors (a protein on the surface of some cancer cells), you may receive targeted therapy drugs^[2].

Surgery options include a lumpectomy, in which a surgeon removes the tumor and some surrounding tissue from the breast, or a mastectomy, in which the whole breast is removed. The surgeon would also remove lymph nodes. After a mastectomy, you might choose to get breast reconstruction surgery^[11]. Radiation therapy is often recommended for women with stage 3 following surgery. The treatment can destroy cancer cells that may have been missed^[11].

Hormone therapy can help women with hormone receptor-positive cancers. That means the cancer needs hormones to grow. In these women, medications can prevent the tumor from getting the hormone^[11]. Targeted therapy is a newer treatment. About 20 percent of women with breast cancer have too much of a protein known as HER2, and it makes the cancer spread quickly. Women with HER2-positive cancer may be prescribed specific targeted therapy drugs^[11].