A GP's View on the Value of Testing

Doctor’s Diary

James LeFanu

Daily Telegraph Monday January 13th 2014

It has taken the experts the best part of 25years to decide that the benefits of the prostate specific antigen (PSA) blood test for those with a “low risk” prostate cancer are so equivocal, the consequences of treatment so adverse that, as recommended last week, patients are much better advised to “wait and see” rather than consent to an operation.

To be sure, the logic behind the test seemed, initially, unassailable, since it can detect the presence of tumour cells in the prostate gland 10 years or more before they become apparent – allowing time to extirpate them before they cause any mischief.

This does, by definition, prevent the cancer from spreading, but the overall impact of the disease has been proved to be much less than predicted, as emerged when researchers anticipating that men from Seattle would benefit from a fivefold higher rate of testing than in Connecticut found the mortality rate to be identical in the two states.

This would matter less were the gland not located in the worst possible place for its successful removal – within millimetres of the bladder and rectum and in proximity to the nerves that control their function. Hence, despite the best efforts of the most accomplished surgeons, the majority of patients are still, a year after surgery, impotent and having to wear adult diapers.

This is an inordinately high price to pay, physically and emotionally, for those with “low risk” cancers who left untreated have, as a study published last year revealed,, a 97per cent chance of being alive 12 years later. The advocates of screening inevitably dispute these figures but, as the developer of the PSA test, Prof Thomas Stamey of Stanford University, subsequently observed, “Never in the history of medicine have so many been over-treated for one disease.”