Monday, January 16, 2006

Testing for prostate cancer is bad for you: "In a carefully designed study, researchers from the Department of Veterans Affairs looked at a group of over 500 patients who had died of prostate cancer, and compared their records with a similar group who had been diagnosed with prostate cancer but had not died from it. They found that those in the first group were just as likely to have been screened for prostate cancer using the PSA test as those in the second group. In other words, PSA testing conferred no survival benefit for these patients...... And the risks of prostate cancer screening are such that it should not be entered into lightly. As usual in debates about screening, there is no such thing as a harmless test. PSA testing is harmful in two ways. Firstly, it has a false negative rate of at least seven per cent. This means that for every hundred men who have the test, 10 will have a raised PSA. All these 10 men will need a prostate biopsy, but only two or three of them will have cancer. So seven or eight cancer-free men will end up having uncomfortable biopsies of their prostate, with potentially serious side-effects such as septicaemia. Secondly, even more problematically, PSA testing does not differentiate between aggressive and potentially fatal cancers, and those which might have had a benign course, never troubling their host. Post-mortem studies have shown that around 40 per cent of men who die aged over 70 have prostate cancer. In the past, most of them would have been blissfully unaware of this fact. In the era of PSA testing, much more of this hidden and harmless prostate cancer is being picked up.... One critic has accurately described this as the 'the eradication of a disease: how we cured symptomless prostate cancer'. Formerly symptomless prostate cancer now has a new symptom: 'a disabling state of anxiety resulting from (men's) knowledge of their PSA level.'"

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