Prostate Cancer

Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. The cancer occurs when cells within the prostate gland become cancerous (malignant), forming a tumour.  When the cancer is contained within the prostate gland, this is referred to as "localised" prostate cancer.  When the cancer has spread to the tissues surrounding the prostate gland, this is referred to as "extracapsular" prostate cancer.

Prostate cancer is the most commonly diagnosed cancer, and the third most common cause of cancer deaths, among New Zealand men. The causes of prostate cancer are not fully understood.  However, it is known that the chances of developing the condition increase with age.  It is also known that prostate cancer is more common in men who have a history of prostate cancer in their family.  Other factors, such as smoking and dietary, hormonal and environmental influences (such as exposure to certain chemicals) may also increase the chances of developing the condition.

Prostate cancer frequently does not produce any symptoms until the condition is quite advanced.  Often it is diagnosed after treatment is sought for problems with urinary function.  Symptoms of prostate cancer are often similar to those of benign (non-cancerous) prostate conditions.

Common symptoms include:
    •    Decreased force of the urine stream
    •    Pain and/or difficulty when passing urine
    •    Passing urine more frequently (especially at night)
    •    Blood in the urine
    •    Inability to pass urine (this can occur as the cancer enlarges, blocking the urethra).
It is possible for the cancer cells to spread from the prostate gland to other areas of the body (metastasise) where further tumours can develop.  The most common places for prostate cancer to spread to are the lymph nodes of the pelvis and the bones of the spine. Spread of the cancer can produce symptoms such as lower back pain.

Common diagnostic tests for prostate cancer include a blood test,  rectal exam,  ultrasound biopsy x-ray, CT/MRi and Bone Scans.

Once a diagnosis of prostate cancer has been made it is important to determine the extent of the cancer.  The cancer is “graded” and “staged” using results of the diagnostic tests. 

Grading indicates the rate of growth (aggressiveness) of the tumour and staging indicates the spread and distribution of the cancer in the body.  The grade and stage of the tumour will determine what sort of treatment will be recommended.

The system used to grade prostate cancer is known as the Gleason Score.  This system assigns a grade of between 1 and 5 to the two most common cell patterns in the cancer, then adds the two grades together to provide the Gleason Score, which can range from 2 to 10.  The higher the score, the more aggressive the tumour is likely to be, and the greater the chance that it has spread within the body.  

The system used to stage prostate cancer is the TNM system.  The "T" refers to the extent of the tumour, the "N" refers to whether the lymph nodes are involved, and the "M" refers to whether cancer cells have spread (metastasised).

T Stages:
T1 - The tumour is confined to the prostate and is unable to be felt or seen on an ultrasound scan.
T2 - The tumour is confined to the prostate but can be felt and is able to be seen on an ultrasound scan.
T3 - The tumour has spread beyond the prostate.
T4 - The tumour has spread to the rectum, bladder or pelvic wall.

N Stages:
N0 - Cancer cells have not spread to regional lymph nodes.
N1 - Cancer cells have spread to regional lymph nodes.

M Stages:
M0 - There are no distant metastases.
M1 - Distant metastases are present.

The choice of treatment will differ for each individual.  A person’s age, general health, grade and stage of the cancer, symptoms, lifestyle and personal choice will all be taken into account.  It is important that time is taken to consider the treatment options available.  Treatment options include, watchful waiting, surgery to remove the prostate, radiotherapy, hormonal treatment or even chemotherapy.