The PSA Test
PSA (prostate specific antigen) is a test for prostate cancer.
However the test is not diagnostic for prostate cancer on its own.
Two thirds of people with a raised PSA do not have prostate cancer.
Prostate cancer can be present with a normal PSA test (6% of prostate cancers).
Perhaps surprisingly, there is no evidence that screening using PSA testing reduces mortality from prostate cancer.
Most prostate cancer is diagnosed in men in their 70s. Most men in their 80s have small numbers of prostate cancer cells – this usually means slow growing, relatively benign cancer which is unlikely to cause harm. Only a small number of men will die from prostate cancer (4%). However about 10% of prostate cancer is diagnosed in men in their 50s.
Testing
DO NOT HAVE A PSA TEST IF:
You have a urinary infection.
You have had sexual intercourse in the last 48 hours.
You have had vigorous exercise in the last 48 hours.
(one study showed a long cycle ride increased PSSA by nearly 10%)
All these are known to increase PSA
Direct pressure from cycling may also increase PSA.
Drinking milk may increase PSA.
If the PSA is high it may be necessary to do a prostate biopsy. If only mildly elevated then monitoring may be all that is needed. Most often with a raised PSA, it will need to be repeated in six weeks.
PSA increases with age. It can be raised in benign prostate disease.
Risks and Benefits
(from US Preventative Task Force)
Out of 1000 men who have a PSA test.
240 will test positive
100 of these will have a prostate biopsy that will find cancer
20-50 % will have a cancer that would never spread or cause harm
80 of these 100 will choose surgery or radiotherapy
50 of those who have treatment will get erectile problems
15 of these who choose treatment will get urinary incontinence
Of these 1000, 1 life will be saved, 3 cancers will be prevented from spreading and 5 will die despite treatment.
