Early diagnostic tests for prostate cancer are so unreliable that doctors would do better to assess the risk through family medical history, cancer experts have suggested.
Ten per cent of sufferers have a brother with the disease, while 5 per cent of patients have fathers who also had the cancer, one recent study revealed (Nature Med, 1995;1 :99-101).
Those with a known family history would benefit more from a test such as prostate specific antigen (PSA), cancer specialists at the Hammersmith Hospital in London have suggested.
One study discovered that 366 men given the "all clear" with a PSA test went on to develop prostate cancer, while raised serum values which indicate the presence of the cancer were found in just 47 per cent of men who had prostate cancer (JAMA, 1995; 273: 289-94).
Similarly, digital rectal examination is only as good as the examiner's ability in detecting the cancer, the specialists say.
Even if successfully detected, the correct treatment from observation through to radiotherapy and radical surgery is another moot point. In one study, the 10 year survival rate among patients who received no medical intervention was 91.5 per cent, while those given radiation therapy had a survival rate of just 77 per cent. Those who have surgery have the best survival rate, but only because they were the youngest and fittest to begin with.
"It is debatable whether treatment for localized prostate cancer is worthwhile in view of the existing options," the doctors conclude (The Lancet, November 4, 1995).