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 further 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 for you.

Cancer stages

Below is an example of a method of staging that may be used:

• stage 0 - indicates that the cancer is where it started (in situ) and isn't spreading
• stage I - the tumour is less than 2cm (0.8 inches) and isn't spreading
• stage II - the tumour is 2-5cm (0.8-1.97 inches) with or without lymph node involvement (lymph nodes are part of the lymphatic system) and hasn't spread
• stage III - the tumour is larger than 5cm (1.97 inches) but fixed either to chest wall, muscle or skin, or has spread to lymph nodes above the collarbone
• stage IV - the tumour is any size - it may affect the lymph nodes but has definitely spread to other parts of the body

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 I - cancer cells that resemble normal cells and aren't growing rapidly
• grade II - cancer cells that don't look like normal cells and are growing faster than normal cells
• grade III - cancer cells that look abnormal and may grow or spread more aggressively

The Macmillan Cancer Support website has more information about the staging and grading of different types of cancer.

Further information:

• Breast cancer
• Lung cancer
• Bowel cancer
• Prostate cancer
• How is cancer treated?
• Am I more at risk if my relatives have cancer?
• Common health questions about cancer