A raised PSA level, or a rapidly rising result, doesn’t necessarily mean cancer. What it indicates is that there are changes within the patient’s prostate that need investigation and explanation. These changes have so many possible causes that what the patient doesn’t need is an inspired guess to explain them, however experienced the clinician.

One of the axioms of medical education was that patients should be spared a dangerous diagnosis made solely on the ground of an experienced doctor’s intuition. The reader needs the opinion of a urologist, careful observation at less than a year’s interval and probably a biopsy. His enlarged prostate causing the nocturnal problems should be treated with something stronger than palmetto. If he also wants natural remedies to keep prostatic cancer at bay, he should cut back on fats and increase his tomato and broccoli intake, and have a glass of pomegranate juice daily. Taking a combination of vegetables of this sort is especially beneficial, as researchers from the University of Illinois announced this week.

An experienced doctor’s intuition is cheap whereas, although the initial PSA is inexpensive, the tests that follow an abnormal reading can be costly and time-consuming. Few aspects of medicine cause more conflict between the interests of cost-cutting and patients’ welfare.

No screening test is perfect because no two people are exactly alike. Even if two people have a similar physical and medical history there is no certainty that a cancer, or precancerous changes, may behave in the same way. It is always difficult to predict outcome with certainty.

Dr Alan Partin, arguably the world’s greatest expert on the significance of the PSA, suggests that a problem is that the PSA is so exquisitely sensitive that the presence of potential disease, or other prostatic changes, can be detected by changes in the PSA years in advance of symptoms. Although many patients need further investigations either because of an apparently raised PSA, or the speed at which it is increasing, so called doubling time, in most cases the changes are apparently a false alarm. Only one man in four with a raised PSA, if it is still under ten, is found to have a cancer, but no one wants to play Russian roulette with one in four rounds in the chamber.

The reading should always be divided into the free PSA and total PSA, descriptions of how the PSA is bound to other proteins in the bloodstream. For some ill-understood reason, if the proportion of unbound, free PSA to the total PSA is reduced the likelihood of cancer is reduced.

The reader’s figures are within normal limits for his age. The usual rough guide is that a PSA should be under either 3 or 4 depending on the doctor’s standard criteria. PSA levels tend to rise with age and perhaps a better guide is that between 40 and 49 it should be below 2.5; between 50 and 59, 3.5; and between 60 and 69, 4.5. Equally important is the rate of increase of the PSA, the pattern of the increase and the doubling time. An unusually rapid increase, despite an otherwise normal result, may indicate a false negative result and the presence of malignancy. Fortunately, any inaccuracy in the PSA test usually involves a false positive rather than a false negative.

Those opposed to the PSA claim that it may lead to expense and anxiety for the patient, but after arranging them for 20 years it seems to me that the numbers suffering from this alleged anxiety are exaggerated, as is occasionally infection from a biopsy. Pain from biopsy is more common than doctors pretend, infection from it much more rare.

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