yyyWHAT IS CANCER?
Clinical Stages of Prostate Cancer
The A,
B, C and D System The
doctor will determine whether cancer is present based on the following
information and tests:
may also be helpful in diagnosis.
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. About 2,500 new cases of prostate cancer are diagnosed each
year.
Men who develop prostate cancer are mostly over the age of 65. It
rarely occurs in men younger than 55. About one in 13 men will develop prostate
cancer before the age of 75. In very elderly men, prostate cancer often grows
very slowly and may cause no symptoms.
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.
DIAGNOSIS OF PROSTATE CANCER
lf cancer is found, the
doctor will do more tests to find out the size and extent of the spread (if any)
of the cancer. Tests may include the following:
Chest
Xray Examination
A standard chest Xray examination can be used to see if the cancer has
spread to the lungs.
Total Body Bone Scan
A bone scan produces a picture which shows whether the cancer has spread to bone. In a total body scan, a very small amount of radioactivity is injected and produces a picture of the bones. If metastases (cancer cells) are present, they will often show up on the scan. The amount of radioactivity is very small and has no significant risk.
CT Scanning (Computerised Tomography)
This technique uses computer technology to produce an Xray picture of the prostate and nearby organs. It is painless and takes about 40 minutes.
Prostate Specific Antigen (PSA)
PSA is a protein produced by cells in the prostate gland. Some men with prostate cancer may have high levels of PSA in their blood.
If cancer is present, the blood level of PSA and how much it changes over the months can tell the doctor whether the cancer is growing, staying about the same, or going away.
Lymph Node Biopsy
To help identify the extent of prostate cancer, lymph nodes near the prostate may be removed. This is usually done either as a staging investigation before planning treatment or during surgery to remove the prostate.
It can be done in one of two ways.
1. during laparoscopy (keyhole surgery), thereby avoiding major surgery to open the abdomen. Laparoscopy is done only in a few patients who may have a high chance of having cancer cells in lymph nodes. Due to recent improvements in tests and diagnosis, doctors can predict more accurately the extent of cancer, which may make laparoscopy unnecessary,
2. during laparotomy (surgery to open the abdomen) to remove the prostate. Note: Microscopic spread of cancer cells cannot always be detected by Xray examinations, scans or clinical examination. However, the level of PSA and grade of the cancer can often predict the risk of microscopic spread.
GLEASON SCOREThe 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.
CLINICAL STAGES OF PROSTATE CANCERThe 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.
THE A, B, C AND D SYSTEMInstead 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.
Stage A (Stage 1)
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.
Stage B (Stage 2)
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.
Stage C (Stage 3)
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.
Stage D (Stage 4)
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.