Staging and grading of breast cancer
Your breast specialist needs certain information about the cancer to help decide on the most appropriate treatment for you. This includes the stage of the cancer, its grade and whether it has receptors for hormones, proteins, or both. Your breast specialist and breast care nurse will talk this over with you.
The stage of a cancer describes its size and whether it has spread beyond the area of the body where it started.
Your surgeon won’t know the stage of the cancer until after your operation and when the results of all your tests are ready.
Number staging system
Breast cancer can be divided into four number stages, which measure the size of the cancer (lump) and whether it’s spread to the lymph nodes or another part of the body.
Stage 1 The cancer (lump) is smaller than, or equal to, 2cm and has not spread to the lymph nodes in the armpit.
Stage 2 is divided into two stages:
Stage 2A – Either the lump is smaller than 2cm and has spread to lymph nodes in the armpit OR it’s bigger than 2cm (but under 5cm) and hasn’t spread to the lymph nodes OR the cancer can’t be found in the breast but is in the lymph nodes in the armpit.
Stage 2B – Either the lump is smaller than 5cm and has spread to the lymph nodes in the armpit OR it’s bigger than 5cm but hasn’t spread to the lymph nodes in the armpit.
Stage 3 is divided into three stages:
Stage 3A – Either the cancer can’t be found in the breast or the lump is under 5cm and the cancer is in the lymph nodes in the armpit, which are stuck together OR the lump is bigger than 5cm and has spread to the lymph nodes.
Stage 3B – The cancer has spread to tissue near the breast and may be attached to surrounding skin or muscle. There are usually cancer cells in the lymph nodes in the armpit as well.
Stage 3C – The cancer has spread to lymph nodes in the armpit, below the breastbone, near the neck or under the collarbone.
Stage 4 – The cancer has spread to other parts of the body such as the bones, liver or lungs. This is called secondary or metastatic breast cancer.
TNM staging system
The number stage is combined with a letter system called TNM, which gives the complete stage of the cancer:
T describes the size of the tumour.
N describes whether the cancer has spread to the lymph nodes and which nodes are involved. For example, N0 is no lymph nodes affected while N1 means there are cancer cells in the lymph nodes.
M describes if the cancer has spread to another part of the body. For example, M0 means the cancer has not spread (metastasised) to other parts of the body.
Other terms used
You may hear some other terms used to describe breast cancer:
Early breast cancer is a term often used to describe stage 1 and 2 breast cancer.
Locally-advanced breast cancer is a term sometimes used to describe stage 3 breast cancers.
Local recurrence means the cancer has come back in the breast area after treatment.
Grading refers to how the cancer cells look under the microscope compared with normal breast cells.
Grade 1 (low-grade) – The cancer cells look similar to normal cells and grow very slowly.
Grade 2 (moderate- or intermediate-grade) – The cancer cells look more abnormal and are slightly faster growing.
Grade 3 (high-grade) – The cancer cells look very different from normal cells and tend to grow quickly.
As well as describing the stage and grade of breast cancer, doctors will also check to see whether the tumour has hormone and HER receptors . Knowing the stage, grade and receptor status helps doctors to choose the most appropriate treatment for you.