Stages of Breast Cancer

Knowing your breast cancer stage is key to a targeted treatment plan

When you’re diagnosed with breast cancer, one of your first concerns is likely whether it’s spread. To answer questions like this, your doctor has to determine the stage.

Physicians use staging to describe how extensive cancer is. Stage includes the size of the tumor and whether it’s spread to surrounding tissues and other parts of the body.

In general, the lower the number, the less cancer has spread. Stage 0 breast cancer is the earliest, non-invasive form of the disease. Stage 4 is the most advanced and means cancer has spread beyond the breast to other parts of the body.

But staging also helps doctors decide how best to treat your cancer — and predicts the chances of that treatment being successful.

“Staging allows doctors to develop a more personalized treatment plan, because each stage presents different therapy options,” says Robin Skrine, MD, a specialist in breast surgical oncology at Geisinger. “A lower stage indicates a more localized cancer, which can mean less aggressive treatments and a more favorable outcome, whereas higher stages of breast cancer can mean more extensive disease. That requires aggressive treatment approaches.”

How stages of breast cancer are determined

Using the results of a physical exam, biopsy and/or imaging tests, your doctor will assign a stage to your diagnosis. The clinical staging system is based on the TNM classification, which evaluates 3 key factors:

Tumor – The size of the tumor
Nodes – The presence of cancer in the lymph nodes
Metastasis – Whether the cancer has metastasized to distant parts of the body

Doctors also use other markers, such as whether the cancer has estrogen, progesterone or HER2 receptors and how quickly the tumor cells are likely to grow and spread.

Together, all of these markers define your stage and offer a more detailed diagnosis and targeted treatment plan.

Stages of breast cancer explained

Breast cancer is classified into 5 main stages, from stage 0 breast cancer to stage 4 breast cancer, each with distinct characteristics and treatment options.

Stage 0 breast cancer

Stage 0 breast cancer, also known as ductal carcinoma in situ (DCIS), is the earliest, non-invasive stage where abnormal cells are contained in the lining of breast milk ducts and have not spread to normal tissues.

Typically, there are no breast cancer symptoms, and the prognosis is excellent. Treatment may include surgical removal of the affected tissue, often followed by radiation therapy.

Stage 1 breast cancer

Stage 1 breast cancer indicates early invasive breast cancer where the tumor is small, measuring up to 2 centimeters (cm), and has not spread beyond the breast. In some cases, however, it could be in a very small number of nearby lymph nodes.

You may notice a lump, nipple discharge or changes in breast shape. The prognosis is excellent, and treatment usually involves a combination of surgery, radiation and possibly hormone therapy and chemotherapy, depending on the tumor’s specific characteristics.

Stage 2 breast cancer

Stage 2 breast cancer is characterized by a larger tumor (between 2 and 5 cm) and/or the cancer has spread to nearby lymph nodes, usually in the armpit.

Breast cancer symptoms may include a noticeable lump or swelling, and breast discomfort. The prognosis remains positive. Treatment often involves surgery, radiation and systemic therapies, including chemotherapy and hormone therapy, depending on your cancer subtype.

Stage 3 breast cancer

Stage 3 breast cancer is more advanced, where the tumor is larger than 5 cm and/or the cancer has spread to many nearby lymph nodes.

This stage often presents with more pronounced breast cancer symptoms, such as lumps in the armpit, nipple and skin changes, and breast pain. The prognosis is favorable, but aggressive treatment is essential. It usually requires surgery, radiation, chemo and targeted therapies.

Stage 4 breast cancer

Stage 4 breast cancer is the most advanced stage, indicating that the cancer has metastasized beyond the breast to other organs, such as the bones, liver or lungs.

Symptoms can be severe and occur in other parts of the body, depending on where the cancer has spread. They may include things like chest pain, chronic cough, bone pain and fatigue. The prognosis at this stage focuses on systemic treatments like chemotherapy, targeted and hormonal therapies to control the disease and manage symptoms.

Breast screenings and early detection

Early detection is the most effective weapon against breast cancer. Besides having regular clinical breast exams, getting a yearly mammogram is the best way to take charge of your breast health.

The recommended age to begin yearly mammograms is 40. However, if you’re younger than 40 and have a family history or other risk factors for breast cancer, talk to your doctor to see if you should start breast cancer screening earlier.

You can control some risk factors for breast cancer by:

Eating a healthy, balanced diet
Exercising regularly
Limiting alcohol
Not smoking
Maintaining a healthy weight

“If you notice any changes in your breasts or develop symptoms, talk to your doctor right away — even if you recently had a clear screening mammogram,” says Dr. Skrine. “The earlier doctors can catch any sign of cancer, the more effectively they can treat it — sometimes with less invasive options.”