The findings are significant because of the large number of American men involved: Over 186,000 are expected to be diagnosed with prostate cancer this year, according to the cancer society, and hundreds of thousands more will be forced to undergo a prostate biopsy after a high reading on a blood test that measures prostate specific antigen (PSA). For most men, the biopsy is negative, their PSA levels being caused by a benign enlarged prostate.
Prostate cancer, which is expected to kill nearly 29,000 American males this year, is a very serious matter. But the condition is unusual in that tumors grow very slowly – so slowly, in fact, that had they not been found a great many men would have died naturally of something else, and without the cancer anxiety.
The recent study, led by researchers at Erasmus University Medical Center in the Netherlands and published by the Journal of the National Cancer Institute, was performed on American men aged 54 to 80, from 1985-2000. It used three different ways of estimating overdiagnosis. The three calculations showed that at least 23 percent and as many as 42 percent of PSA-detected cancers would otherwise never have been detected in a man’s lifetime.
Overdiagnosis is a problem because once a tumor is found, a man faces a life-altering decision: Should he engage in “watchful waiting,” surgery, hormone therapy or radiation treatment? Some of these can leave a man incontinent or impotent, and if a man’s tumor is of the non-threatening kind, he’s made a very bad decision.
It comes down to: “If we diagnose this disease, are we making your life better?” said Lichtenfeld. “We know that [to be the case] for other cancers,” such as lung, breast and colorectal, which have overwhelming evidence showing that early detection greatly improves survival.
So researchers are now looking feverishly for ways of distinguishing between threatening and non-threatening prostate tumors.