Grades of prostate cancer

The pathological grade of a cancer is the term used to describe how aggressive the disease is and whether it will progress (grow) quickly (months) or slowly (years). The grading assessment is made by a pathologist in the laboratory, looking at cells from the biopsy sample under the microscope. If cancer cells are found in the biopsy samples, the pathologist will ‘grade’ them. The grading system used for prostate cancer is known as the Gleason scoring system, named after the pathologist Donald Gleason. The score ranges from 2–10.

The pathologist will identify several of the prostate cancer cells in the biopsy. Having identified the largest and second largest areas of cancerous cells, they will assign each area a number known as the Gleason grade. These grades range from 1–5, with grade 1–3 tumours least likely to spread and grades 4 and 5 most likely.

Gleason Scale - Microscopic appearance of prostate tissue