DIAGNOSTIC

How is prostate cancer diagnosed?

The diagnosis of prostate cancer can be confirmed by a biopsy.

A urologist (a doctor who specialises in diseases of urinary and sex organs in men and urinary organs in women) remove tissue samples, usually with a needle. This is generally performed in a doctor's suite with local anesthesia. The urologist will insert a small ultrasound probe and sampling needles into the anus.

The ultrasound will generate an image of the prostate on a computer screen and guides the doctor into inserting the sample needles into the affected areas of the prostate. The doctor will take at least 6 samples. A biopsy is not always performed under anaesthetic and there may be some pain and bleeding. There is a small risk of infection, so antibiotics are given to reduce the risk of infection.

A pathologist will then examine the cells to see if cancer is present. If cancer is present, the pathologist will make the following assessments.

Prostate Cancer is determined by both stage and grade. The stage reflects how far the cancer has developed (its relative size) while the grade is how aggressive the cancer is and how quickly it is likely to develop.

The development of prostate cancer is typically divided into five stages:

T1 Stage
The tumour is located within the prostate gland and is too small to be detected during a rectal examination, but it may be discovered through other diagnostic procedures such as the PSA test. Prostate cancer at this stage generally produces no symptoms.

T2 Stage
The tumour is still located within the prostate gland but it has grown to a point where it can be felt during a DRE exam or imaged by ultra sound or other types of imaging study. There are often very few symptoms.

T3 Stage
The tumour has spread beyond the prostate to other areas near the gland. A common symptom at this stage is difficulty in urinating.

T4 Stage
The tumour has spread and become fixed to other adjacent parts of the body, such as the bladder, other organs or to the bone.

Metastatic
The tumour has spread and become fixed to other adjacent parts of the body such as the bladder.

Grading of the prostate cancer

In addition to determine the stage, prostate cancer is graded to determine how aggressive or fast growing the tumour is. The grade is assessed under a microscope, with the pathologist determining how much the tumour resembles normal prostate tissue. Normal cells have certain distinguishing characteristics.

Depending on the deterioration, the grade is allotted. The grades range from 1 to 5 and the lower the grade the more that they resemble a normal cell. Grade five for example would mean that the cells are badly degraded and grade four, the cancer is generally fast growing and beginning to spread.

There are several grading systems, but the Gleason system is the most common. The definitive Gleason score is computed by adding together the primary grade of the largest component with that of the next largest different component; hence it ranges from a score of 2 (the lowest) to 10 (the highest grade of tumour).

Lower scores (2 to 4) mean that the cancer cells look similar to the normal cells and are usually less aggressive and much slower to progress.

A score of 5-7 is intermediate whilst a score of 8-10 means that the cancer cells are more likely to be aggressive and more likely to spread.

The volume of the cancer present at diagnosis is another important factor as to whether the cancer is curable.