By the way ... The men who MUST have cancer tests

WHEN prostate specific antigen (PSA) testing was introduced some 30 years ago, doctors were pleased at last to have a means of screening men for prostate cancer.

Most don’t have symptoms until the cancer has spread, so being able to identify — and therefore treat — it early seemed like the Holy Grail had been found.

But it soon transpired that this test (which measures levels of a protein produced by the gland) was a false dawn.

Studies in subsequent years have cast a shadow over it, on account of the high false positive rate — more than 20 per cent of men with a raised PSA do not have prostate cancer at all (raised levels can also be a sign of an enlarged prostate, for example).

What’s more, although a positive test in some men does indicate cancer, a proportion of those tumours are so slow growing as to never be life-threatening. This can lead to a situation in which treatment is more disabling than the cancer itself — in other words, the test has led to over-diagnosis.

Medical professionals are still divided about the effectiveness of PSA testing and the ratio of benefits versus harm.

The best summary of the evidence is that for every 1,000 men who undergo screening several times each over ten or more years, one death from prostate cancer will be avoided.

But that is set against the many men who will be damaged by radical prostatectomy, radiotherapy, hormone therapy and other cancer treatments, which carry the risk of urinary incontinence, erectile dysfunction, or bowel problems.

However, it now seems that the pendulum has swung too far the other way.

As many as one in ten men who request PSA screening are turned down by their GPs, the charity Prostate Cancer UK reported last week. Yet we know that about one in eight men will get prostate cancer, rising to one in four men who have a family history of the disease (such as a brother or father who had it).

These are the very men who should be screened, along with those with family history of the faulty BRCA gene and black men (all these groups have a significantly higher risk).

What all this means is that doctors and patients must bear in mind what I so often bang on about on these pages: screening must be structured to the risks of the individual and not simply a blanket edict.

Care must be taken to go through the patient’s history so that doctor and patient can decide, together, whether to screen or not. And that takes time.