Prostate Cancer: Diagnosis
The first tests that the GP performs are a digital rectal examination (DRE) and a blood test to measure prostate-specific antigen (PSA). The normal level of PSA in the blood is less than 4.0 ng/ml. Elevated levels do not necessarily indicate cancer. Any disease of the prostate � particularly BPH, but also prostatitis � can result in an elevation of the PSA, though usually to a rather minor extent. One in five men with a PSA value between 4 and 10 ng/ml will have a positive biopsy for cancer (so four of the five will not have cancer though their PSA level is raised).
Figure 5: Digital rectal examination
Test results can take anything from a couple of hours to a week or so depending on where you had the test. Over-the-counter PSA tests may soon be available in chemist shops allowing self-testing.
The pros and cons of PSA testing are shown in the table below.
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Pros of PSA testing |
Cons of PSA testing |
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A raised PSA: what next?
If your GP finds that you have a raised PSA level (one above 4 ng/ml), you will probably be referred to an urologist � a specialist in disorders affecting the genitourinary tract in men (and the urinary tract in women). It is vital that you feel comfortable with, and confident in, your urologist. You should understand his explanations of procedures and options, and he should be prepared to discuss fully anything that is concerning you or your partner. In this day and age, don�t accept that the �doctor knows best� � it�s your health and peace of mind at stake here, so make sure that you�ve had all your questions answered before you leave the consultation room. If you are not happy with your urologist, go back to your GP and discuss the matter with him.
You may decide that you would like to see another urologist. If so, tell your GP and ask him to organize this. Alternatively, you may want to find your own specialist on a private basis. If this is the case, the first thing to do is to check your health insurance, if you have it. Some companies will not cover your expenses unless you have been referred by your GP. Also, you (or your insurers) may want to check the prices of treatment at an early stage. The clinic should provide a price list for you � if they do not, talk directly to the urologist. If you aren�t happy with your service, talk to the clinic manager or urologist directly � you are a prospective customer and they will be unlikely to want to �lose� you. If you are still not happy, go back to your GP (it�s important to pass on your experiences of private clinics to GPs so that they know who to recommend to other patients).
Diagnostic tests
Your urologist may repeat the tests that your GP has already carried out. A number of other tests may be carried out including:
- Urine test: To checked for bacteria, as you may have a urinary tract infection, and/or blood, as this can develop if the prostate cancer has spread into the urethra
- Physical examination: to check your general state of health
- Urination questionnaire: this is completed by the patient himself and will give information on urinary symptoms that could be due to prostate cancer or BPH
Prostate biopsy
If cancer is suspected a prostate biopsy will be performed to remove tiny pieces of prostate tissue for examination. After you have been given antibiotics, up to six samples of prostate tissue are removed using a very fine needle inserted via the rectum. Ultrasound is often used to �guide� the biopsy needle. A finger-sized probe is inserted into the rectum and it passes inaudible sound waves through the prostate that produce an image of the gland on a computer screen. Biopsy is uncomfortable but not very painful, though the needle prick can be felt.
Antibiotics will be continued for several days after the test. Also, blood may be seen in the urine, semen or bowel movements for several weeks.
Figure 6: Prostate biopsy
Grade and stage
Biopsy tissue samples are examined to measure how advanced the cancer is.
The most common grading system is the Gleason system. The higher the grade the more aggressive is the cancer. The cancerous areas in the prostate may vary and have different grades, so the numbers of the two most prominent grades are added together to give a Gleason score (for example, 3 + 4). This figure then gives you and your doctor an idea of how quickly your cancer is likely to progress.
The cancer can also be classified according to how far it has spread � its �stage�. The tumour�nodes�metastasis (TMN) system is commonly used, and involves the doctor assessing how far your cancer has spread in and around the prostate, whether it has spread to the nearby lymph nodes and then whether it has spread to the distant lymph nodes and bones. Knowing the stage of your cancer helps your urologist to decide on the most appropriate course of action.
Bone scans
Bone scans may be necessary if the urologists thinks that the cancer may have spread outside the prostate. Several hours before you have the scan, a mixture containing radioactive particles (radionuclides) will be injected into your arm. The particles then distribute around your body; their pattern, which shows up on the scanner, can reveal areas of abnormal blood flow � a sign that cancer may be present. Don�t be concerned about the use of radiation here � the amount is so low that the risk to your health is negligible.
MRI and CT scanning
Several pictures of the body at different points are taken in this procedure, rather like slices through a loaf of bread. The images produced allow the urologist to assess the extent of the cancer in the prostate and to check whether any secondary tumours have formed in other regions.