Grading refers to the appearance of the cancer cells when the biopsy sample is looked at under the microscope. The grade gives an idea of how quickly the cancer may develop. There are several grading systems, but the Gleason system is the most commonly used. This system looks at how the cancer cells are arranged within the prostate and grades them from 3–5. The two most frequent patterns of prostate cancer growth are assessed and the grades added together to give an overall score from 6–10. The lower the Gleason score, the lower the grade of the cancer. Low-grade cancers (6) are usually slow-growing and less likely to spread. A score of 7 is a moderate grade. High-grade tumours (8–10) are likely to grow more quickly and are more likely to spread.
Staging of cancer is done to assess the degree of its malignancy. It helps to know the prognosis and to decide the treatment of a cancer patient. Staging is determined by different parameters such as size of the tumour, involvement of the lymph nodes and the extent of metastases. There are different staging systems such as Dukes staging system and Astler Coller staging system. The internationally recognised staging system is known as TNM classification. It is based on the number or size of the primary tumour (T), spread to the lymph nodes (N) and the presence or absence of metastases (M). The letter (T) is followed: by X if the primary tumour can not be assessed clinically, by 0 if there is no evidence of primary tumour, by IS if the tumour is in situ and by a number 1, 2, 3 or 4, which denotes the size of tumour. The greater the number, the larger is the size of tumour. The letter (N) is followed by x if the regional lymph nodes can not be assessed clinically, by 0 if regional lymph nodes are not involved and by a number 1, 2, 3 or 4, which denotes the extent of lymph node involvement. The letter (M) is followed by X if the presence of distant metastasis cannot be assessed clinically, by 0 if there is no evidence of metastasis and by 1 if the cancer has metastasised. These numbers are usually translated for convenience of the patients as Stage I, Stage II, Stage III and so on.
