The stages of breast cancer explained

Breast cancer is the most common cancer in the UK. Thankfully, if it is detected early, you stand a very good chance of making a full recovery. By learning what symptoms to look out for, you can greatly improve your chances of early diagnosis so you can get treatment as soon as possible. 

The progression of breast cancer is divided into five stages — stages 0 to 4. These are often subdivided into categories A, B and C. Once a case of breast cancer has been assigned a particular stage, a doctor specialising in treating cancer (an oncologist) can identify an appropriate course of treatment. 

Stage 0

This means the cancer has been diagnosed early and is usually confined to where it started in either the breast ducts or milk glands — this is sometimes described as being ‘in situ’. 

Although treatment at this stage is often successful with five-year survival rates at around 100%, it is very important to start treatment as quickly as possible. A common first treatment is a lumpectomy, where the abnormal cells and some of the surrounding breast tissue are removed. A lumpectomy is often followed by a course of radiotherapy to kill off any remaining abnormal cells. 

Hormone therapy may also help prevent more cancer cells from developing in the breast. This involves either reducing the levels of certain hormones in your body or preventing these hormones from reaching the cancer cells.  

Stage 1

Stage 1 breast cancer is invasive which means it has spread beyond the tissue it originated in and into healthy tissues. At stage 1A, the cancer has spread into the fatty breast tissue and the tumour is small. At stage 1B, you may or may not have a tumour in your breast but you will have clusters of cancer cells that have spread into your nearby lymph nodes (a part of your immune system).

Surgery is a standard treatment at this stage. Tumours are usually small and can be removed through a surgery called a lumpectomy — you may also need to have one or more of your lymph nodes removed. You may be recommended radiotherapy, hormone therapy and/or chemotherapy after your surgery. 

Newer treatments such as targeted therapy, which specifically blocks the growth of cancer cells, may also be offered to treat breast cancer at this stage. 

Five-year survival rates for stage 1 breast cancer are around 100%.

Stage 2

At stage 2, the tumour has grown, the cancer has spread or both. Stage 2A means that if there is a tumour, it is still considered small. The cancer may not have spread to your lymph nodes or it may have spread to as many as three. By stage 2B, any tumour in the breast has grown bigger but the cancer may or may not have spread to the surrounding lymph nodes. 

If the tumour has grown significantly, you may be offered chemotherapy to shrink it before undergoing surgery. If successful, this may mean that a lumpectomy is enough to remove the cancer. However, often a mastectomy (complete removal of the breast) is needed followed by either radiotherapy or further rounds of chemotherapy. 

The survival rates for stage 2 breast cancer are still high, with over 90% of patients living for five years or more after treatment. 

Stage 3

Although stage 3 cancer may not yet have spread to your bones or organs, it’s still considered advanced and is harder to treat. Stage 3A means that the cancer has been found in more of the lymph nodes in your armpit (axillary lymph nodes) or is affecting the lymph nodes near your breastbone. In some cases a large tumour may be detected but sometimes there will be no tumour present. Stages 3B and 3C mean that a tumour has grown into the chest wall or perhaps the skin around the breast. Your cancer may have spread to 10 or more lymph nodes or may have spread above the collarbone. Stage 3C can also mean that lymph nodes near your breastbone have become enlarged and cancerous. 

Treatment at this stage will usually begin with chemotherapy to try and shrink any tumour present and kill off cancer cells before surgery. You may then be offered a mastectomy. 

After surgery, you may be offered radiotherapy and hormone therapy to destroy any remaining cancer cells and prevent the cancer from coming back. 

Although breast cancer is harder to treat by this stage, almost three-quarters of patients survive for five years or more after treatment. 

Stage 4

By the time breast cancer reaches stage 4, the cancer cells have spread far away from the breast and surrounding lymph nodes. This is called metastasis and most commonly affects the lungs, liver and brain. 

Once the cancer has spread to this extent, treatment will very rarely cure the disease but can slow down its progression. Patients with stage 4 breast cancer can live for years but their lifespan will be shortened. Five-year survival rates at this stage are around 22%. 

Chemotherapy is the most common treatment offered at this stage and is often used in combination with hormone therapy. However, targeted therapy and immunotherapy are also options that your doctor may discuss with you. Other treatments may be offered to relieve the symptoms of more advanced breast cancer. 

Looking after yourself following a diagnosis

If you have had a diagnosis of breast cancer, you may feel anxious about the road ahead. It’s important to focus on your wellbeing after a diagnosis. This can help you cope with both the physical and emotional strain of treatment. 

Maintaining a healthy diet and staying hydrated will help support your body throughout your treatment. Try to eat more fresh fruit and vegetables and eat fewer fatty foods as well as pickled, smoked and cured foods. 

While it can be challenging, adopting a positive attitude can help keep your focus on positive outcomes. Mindful practices can help, such as yoga and meditation. This is especially important during active treatment. 

Having someone to talk to can also help. If there is no one you feel comfortable turning to, there are many organisations which offer support and advice.