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What do cancer stages and grades mean?

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

Stages of cancer on Cancer Research UK website

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

Find out more about the grades of a cancer

Cancer grading on Cancer Research UK website

Further information

Page last reviewed: 16 December 2021
Next review due: 16 December 2024