PROSTATE CANCER: THINK BEFORE HAVING A PROSTATE PROBE
Every day dozens of Australian men unwittingly step onto the slippery slope of prostate cancer investigation.
They do this through ignorance. They submit themselves to a blood test without understanding where it may lead and without taking steps to minimise their chance of a false result. As a consequence, many find themselves halfway down the slope, in a state of great anguish, only to be told there was never any cancer.
Those who learn they do have cancer face a new set of decisions, and the way ahead for them is far from clear. Before a man submits himself to a routine blood test for prostate cancer there are a few things he should know.
The first is that the test is not accurate. Although it is the best available simple indicator, it is not a perfect diagnostic tool. It is only about 66 per cent reliable. The second is that, even if the test hits the mark and cancer is detected, a positive result does not mean this cancer is necessarily fatal or even harmful. Some men live harmoniously with prostate cancer for decades without discomfort.
If the cancer needs treatment, no-one will be able to say with certainty which approved treatment will be most successful: surgery, radiotherapy, hormone therapy or watchful waiting (vigilance without active treatment).
It is also worth knowing that in the case of prostate cancer the cure is sometimes worse than the condition. The typical response of wanting the cancer out and in the bucket may seem reasonable, but prostate cancer is different from other cancers, and the procedure may leave a man with bigger problems than the cancer would have caused had it been left untreated.
Several factors can affect the result of this test, and men not wanting to cause themselves unnecessary anxiety should take precautions against a false result (see box). The test for a prostate-specific antigen, called a PSA, indicates the presence of a protein in the blood. The production of this protein is one of the normal functions of the prostate.
Large amounts of PSA are present in semen and appear to play a role in preventing semen becoming too thick. However, small amounts of PSA also normally enter the blood. As men age, the amount of PSA entering the blood usually increases, probably because the prostate increases in size and perhaps because the prostate cells become weaker and allow more PSA to seep out. To take account of this increase, standardised normal limits of PSA in the blood have been set for men of different ages.
The first precaution men should take is to avoid sex for 48 hours before the test. Research shows that in older men ejaculation causes a significant increase in the concentration of PSA in the blood. Several layers of tissue keep the PSA inside the prostate, and with age these tissues deteriorate. With ejaculation, the muscle of the prostate contracts and relaxes, basically massaging the gland and facilitating the escape of PSA through the deteriorating tissue into general circulation.
One study of men between the ages of 49 and 79 found this increase takes 2 days to subside. In the study, PSA levels peaked an hour after ejaculation, when 87 per cent of the men demonstrated a 60 per cent increase. After 2 full days, the levels were back to normal in 97 per cent of them. ‘I’he rise in PSA levels was so marked that 15 per cent of the men in the study would have wrongly qualified for a transrectal ultrasound and prostate biopsy if an assessment had been made based on their PSA levels soon after ejaculation. A similar rise in PSA levels after ejaculation has not been noted in young men.
There is no evidence that a routine digital examination, in which the doctor inserts a gloved finger into the rectum and takes 15 or 20 seconds to palpate the surface of the gland, will have an effect on PSA levels. There is, however, evidence that an aggressive examination or prostate massage will affect the PSA reading and elevate it. If the doctor pushes and presses the prostate, moves it around and generally beats it up it will have an effect. As he puts pressure on it, secretions in the tissues are expressed and more PSA can escape into the blood.
Having prostatitis – an infection in the prostate – can also elevate PSA levels. The elevation can last weeks or months, and one particular form – acute bacterial prosiatitis – inflames the gland, making it hot, swollen and tender. This allows more PSA to escape into the blood. Urinary retention, and in particular urinary tract infections, may also elevate PSA levels. In the case of retention, the strain and pressure on the prostate and the effects of catheterisation (if required) also cause a slight rise.
FACTORS THAT MAY ELEVATE PSA LEVELS
ejaculating in the 48 hours before the test
having prostatitis – an infection of the prostate
a vigorous rectal examination including prostate massage
urinary retention and/or urinary tract infections
15PI I – benign prostatic hyperplasia or prostate enlargement
TURP – transurethral resection of the prostate
prostate biopsy.
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