Prostate Cancer

Prostate Cancer

To get checked for prostate cancer please consult with your GP.

The human body is made up of billions of tiny building blocks called cells. Sometimes, cells reproduce in an uncontrolled way and grow into a lump, or tumour.

There are two kinds of tumours: noncancerous (benign) and cancerous (malignant). Benign tumours do not spread to other parts of the body and are not life threatening (except in very rare situations).

Cancerous tumours can attack nearby cells and destroy them. Cancer cells can also get into body fluids and spread to other parts of the body. This is called a secondary cancer or metastasis. Blood and lymph are the fluids which transport cancer cells to other parts of the body. Lymph is a nearly clear fluid that travels through lymph vessels and small oval structures called lymph nodes. Lymph fluid eventually mixes with blood which travels throughout the body.

Cancer is not a single disease with one cause and one type of treatment. There are more than 200 different types of cancer. Each has its own natural course of development and response to treatment.

Cancer of the Prostate

In New Zealand, prostate cancer is the most common cancer in men, with over 3,500 registrations and more than 650 deaths each year (based on the statistics from the Ministry of Health 2018).

Some men are more at risk of getting prostate cancer than others, but the most important risk factor is ageing. Men with a family history of prostate cancer have a higher risk; that is, if the father, an uncle or a brother has had prostate cancer.

Doctors do not know what causes prostate cancer. They do know, however, that the growth of cancer cells in the prostate is stimulated by male hormones, especially testosterone. Most prostate cancer growth is influenced by testosterone.

The speed at which prostate cancer grows varies from man to man. In some men the cancer grows very slowly; in other men, it grows more rapidly.

A cancer is often very hard to find when it is located only within the prostate. This is because it may not cause symptoms and may be too small for a doctor to feel during a routine rectal exam.

A man with slow growing prostate cancer may live for many years and die of other causes, without ever having symptoms of prostate cancer. If the cancer grows too much, however, the prostate usually squeezes the urethra, which it surrounds. Symptoms may then start, such as difficulty in passing urine. As the same symptoms can be caused by other problems, difficulty in passing urine does not always mean that prostate cancer is present.

A growing cancer can affect cells close to the prostate. At the same time, cancer cells may get into the blood and spread to other parts of the body, especially the bones. A man may not have any symptoms during the early period of cancer spread.

Prostate cancer tends to spread to lymph nodes, bones (especially ribs and bones around the hip and lower back), liver and lungs. Cancer cells that have spread to other parts of the body will grow, causing symptoms such as bone pain, one of the most common problems.

Gleason Score

The pathologist examines the biopsy specimen and grades it on a scale of 2 to 10. This “Gleason Score” indicates how aggressive the cancer is and how fast it is growing; the higher the score, the more aggressive and faster growing the cancer is.

Clinical Stages of Prostate Cancer

The TNM System and Common Treatment Choices

This next section is a little technical, but you may wish to read it to understand how doctors define the stages of prostate cancer.

The most commonly used staging system is the TNM System, which stands for:

  • Tumour (indicates the size or involvement of a malignant tumour)
  • Node (indicates whether lymph nodes have cancer cells in them)
  • Metastasis (indicates whether cancer has spread to other parts of the body)

The stages are called T1, T2, T3 and T4, N0 and N1, and M0, and M1.
T1, T2, T3 and T4 have substages: T1a, T1b and T1c; T2a, T2b and T2c; T3a, T3b and T3c; and T4a, and T4b.

Where an ‘X’ is shown, it indicates that either lymph nodes or metastases cannot be evaluated. Your doctor can tell you more about staging and its importance to the treatment options. The doctor will estimate how much cancer is in the prostate and may be able to estimate how fast the cancer is growing. This information will influence the doctor’s advice about which treatment is likely to be best.

TNM System
T1 T2 T3 T4
N0 NX N1
M0 MX M1

Click on the relevant stage for more information.

The A, B, C and D System

Instead of the TNM System, some doctors talk about stages A, B, C and D. Sometimes these stages are called 1, 2, 3 and 4, respectively.

In Stage A, the tumour is confined to the prostate gland only and cannot be felt during a prostate examination via the rectum.
If found at all, it is usually found by chance during treatment for BPH, prostatitis, or some other prostate problem.
Cancer cells may be found in only one area of the prostate or in many areas of the prostate.

The tumour is located within the prostate only but can be felt during a prostate examination via the rectum. The man may or may not have symptoms. Blood levels of PSA are usually increased.

The tumour has spread from the prostate to other nearby tissues.
The seminal vesicles, the glands that produce semen, may have cancer in them. Difficulty in passing urine is a common symptom.

The tumour has spread to other parts of the body, most often the lymph nodes, bones, liver or lungs. Difficulty in passing urine, bone pain, weight loss and tiredness are common symptoms.

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