The biopsy provides information about the type and grade of the cancer. The grade of the cancer shows how fast the cancer might grow, and the stage shows how far it has spread.
Grading: The Gleason system
Normal tissue has an ordered pattern of growth but in cancer tissue, the pattern is not ordered because of the unpredictable way cancer cells grow. The Gleason scoring system is used to show how abnormal or different the cancer tissue is, compared to the normal tissue. The two most common patterns of growth seen are each given a number from 1 to 5, and then the two numbers are added to give the Gleason grade (e.g. 4+3=7). The greater the difference, the higher the Gleason score, and the more aggressive the cancer acts in the body.
Cancer cells on the Gleason grade scale - from 1 (least aggressive) to 5 (most aggressive).
Staging: the Tumour-Node-Metastasis (TNM) System
The standard TNM system is used to work out the stage of different cancer types, indicating how far the cancer has spread from the prostate. This is usually worked out using imaging such as MRI or CT scans of the abdomen and pelvis, a nuclear bone scan, and in some cases PET scanning.
The TNM staging system has 3 scores:
- The local stage of the tumour (T Stage)
- Whether the cancer has spread to the lymph nodes (N Stage)
- How far the cancer has spread (M Stage).
This information, combined with your Gleason score, guides decisions about the best treatment approach.