Prostate screening


Screening for disease can be complex. While it is intuitively logical to pick up cancer cases as early as possible, current screening methods are associated with significant levels of over diagnosis. The publication last week in the Lancet of a major study on screening for prostate cancer is a case in point. Despite finding that screening for the cancer using a prostate-specific antigen (PSA) blood test had the potential to reduce deaths from the disease by about 20 per cent, the authors of the study were unable to recommend the use of routine screening programmes for prostate cancer because of doubts as to whether the benefits outweighed potential harms.

The European Randomised study of Screening for Prostate Cancer, based on some 13 years of findings on the effects of screening on more than 162,000 men showed that screening appeared to cut deaths from the disease by 22 per cent after 11 years. However, over diagnosis occurred in about 40 per cent of those studied, meaning they were exposed to unnecessary investigation, and, in some cases, unwarranted treatment. In addition, up to a half of those screened were diagnosed with prostate cancer that would never do any harm and not lead to death. The US Preventive Services Taskforce has ruled that the routine use of the PSA test as a screening mechanism did more harm than good. Its decision came amid concerns that some men, after routine screening using PSA, were being treated for a form of the cancer that was unlikely to shorten their lives.

Prostate cancer, which is diagnosed in some 3,200 men here each year, is usually slow-growing. But there are exceptions: a minority of men get a more aggressive form. What is needed now is the development of more refined technology to selectively diagnose aggressive prostate cancers.

There is a need to decouple diagnosis from intervention: men with inconsequential tumours must no longer be saddled with unnecessary worry.