Breast cancer
Treatment of breast cancer and staging
The treatment of breast cancer depends on several key factors, including how advanced the cancer is, the specific type of cancer, and the results of certain lab tests that help assess risk.1,2
Before treatment begins, your care team will carry out a number of tests to understand your cancer better. This includes a biopsy to study the cancer and nearby lymph nodes. These samples are examined to determine the exact type of the cancer, and whether the cancer is influenced by hormones (oestrogen or progesterone) or growth proteins. Additional tests, such as gene expression analysis, may be used in some cases to guide decisions around the need for chemotherapy.1,2
Understanding Breast Cancer Staging
Staging is the process used to describe how big the cancer is, where it is located, and whether it has spread to other parts of the body. Knowing the stage of the cancer is essential, as it helps your doctor determine the most appropriate treatment plan and understand the likely course of the disease.
There are two main types of staging:
- Clinical staging: Takes place before any treatment and is based on a physical exam, blood tests, and imaging scans.
- Surgical staging: Takes place after surgery and is based on examination of the tissue that has been removed.
To get a complete picture of the cancer, your care team may recommend additional imaging tests. These can include:
- CT scan: A detailed x-ray that shows a cross-section of the internal organs.
- MRI scan: Uses magnets and radio waves to create detailed images of the body.
- Bone scan: Uses a small amount of radioactive material to check for cancer in the bones.
- PET scan: A scan that uses a special dye to detect areas of cancer that other scans might miss. It is often combined with a CT scan.
A lymph node biopsy is often performed as part of staging. This may include a sentinel lymph node biopsy, a technique that identifies and tests the first lymph node most likely to contain cancer cells. This approach helps determine whether the cancer has started to spread beyond the breast. It is also an important step in planning treatment, because when the sentinel node is found to be free of cancer, some women can safely avoid chemotherapy.1,2
The stage of a breast cancer describes how far the disease has progressed in the body according to the TNM system.3 It takes into account the size of the Tumour (T) in the breast, whether cancer has reached nearby lymph Nodes (N), and whether it has Metastases (M), meaning it has spread to other parts of the body, such as the bones, liver or lungs. Doctors usually describe breast cancer using stages from 0 to IV, which range from very early disease confined to the milk ducts, to cancer that has spread to distant organs.3,4 In general, lower stages mean smaller cancer and less spread, with a better prognosis. Your doctor will explain exactly which stage applies to you and what it means for your care.1
| Stage | What it Means | Key Features |
| Stage 0 | Very early breast cancer that has not invaded surrounding tissue. |
|
| Stage I | Small, early invasive breast cancer.
This is often called early‑stage breast cancer. |
|
| Stage II | Larger tumour and/or limited spread to lymph nodes. |
|
| Stage III | More extensive disease in the breast or lymph nodes.
This can be called “locally advanced” breast cancer. |
|
| Stage IV | Cancer has spread to other parts of the body.
It can be referred to as advanced breast cancer. |
|
Another important factor is the grade of the cancer, which refers to how abnormal the cancer cells look under a microscope and how quickly they are growing. Grades range from 1 to 3 – higher grades indicate faster-growing, more aggressive cancers.1,4
| Stage | What it Means | Key Features |
| Grade 1 | Sometimes called “well differentiated” or “low grade”. |
|
| Grade 2 | Sometimes called “moderately differentiated” or “intermediate grade”. |
|
| Grade 3 | Sometimes called “poorly differentiated” or “high grade”. |
|
Understanding your cancer’s stage, grade, and biology helps your care team choose the most effective treatment. This is a complex process, but you are not alone. Your case will be reviewed by a multidisciplinary team, including surgeons, oncologists, nurses and other specialists who will work together to recommend the best treatment plan for you. These discussions will also take your individual preferences, needs, and lifestyle into account.1
For patients with symptoms or a higher stage of the disease (for example, Stage II or above), further scans may be recommended to check whether the cancer has spread to other parts of the body, such as the bones, liver, or lungs. If a person has a strong family history of cancer or meets certain criteria, genetic testing may also be offered, especially if targeted treatments are being considered.2
It is also worth noting that some groups of patients – such as younger or older individuals – may need slightly different treatment approaches. However, treatment decisions should be based more on a person’s overall health than on age alone.2
Sources
- ESMO. Breast Cancer: A Guide for Patients. (2018).
- Loibl, S. et al. Early breast cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann. Oncol. 35, 159–182 (2024).
- Breast Tumours. (OMS, Geneva).
- Cancer Research UK. About breast cancer staging and grades. https://www.cancerresearchuk.org/about-cancer/breast-cancer/stages-grades/about (2023).
