The stage of a cancer describes the size of a tumour and how far it has spread from where it originated. The grade describes the appearance of the cancerous cells.
If you're diagnosed with cancer, you may have more tests to help determine how far it has progressed. Staging and grading the cancer will allow the doctors to determine its size, whether it has spread and the best treatment options.
Cancer stages
There are 2 main types of staging systems used for different types of cancer.
Number staging system
Sometimes doctors use a number staging system.
The number stages are:
- stage 0 – the cancer is where it started (in situ) and hasn't spread
- stage 1 – the cancer is small and hasn't spread anywhere else
- stage 2 – the cancer has grown, but hasn't spread
- stage 3 – the cancer is larger and may have spread to the surrounding tissues and/or the lymph nodes (or "glands", part of the immune system)
- stage 4 – the cancer has spread from where it started to at least 1 other body organ, also known as "secondary" or "metastatic" cancer
TNM staging system
The TNM system uses letters and numbers to describe the cancer. This system is used in different ways depending on the kind of cancer you have.
For the TNM system:
- T describes the size of the tumour, with numbers 1 to 4 (1 for small, 4 for large)
- N stands for lymph nodes, with numbers 0 to 3 (0 means no lymph nodes have cancer, 3 means many do)
- M stands for metastases or whether the cancer has spread to another part of the body, with numbers 0 or 1 (0 means it has not spread, 1 means it has)
Find out more about cancer stages
Cancer grades
The grade of a cancer depends on what the cells look like under a microscope.
In general, a lower grade indicates a slower-growing cancer and a higher grade indicates a faster-growing one. The grading system that's usually used is as follows:
- grade 1 – cancer cells that resemble normal cells and aren't growing rapidly
- grade 2 – cancer cells that don't look like normal cells and are growing faster than normal cells
- grade 3 – cancer cells that look abnormal and may grow or spread more aggressively