Exploring recent improvements in prostate cancer

Reported by Susan Aldridge, PhD, medical journalist

An evaluation study suggests that it is reclassification - rather than real improvements - that has led to recent increases in survival in prostate cancer.
In the past decade, there has been a welcome improvement in prostate cancer survival. But how much of this is linked to changes in diagnostics and how much to better treatment? To find out, a team at the University of Connecticut had a look back at samples from 1,858 men diagnosed with prostate cancer between 1990 and 1992. They had an experienced pathologist grade the tumors by the Gleason number, a measure of how likely it is the tumor will spread. The scale goes from 2 to 10 and it's unusual, these days, for a tumor to be graded less than five.

The results showed that there has been a real shift in evaluation of tumors. The original average Gleason score for these tumors was 5.95 and now it is 6.8. Over half the specimens, when re-examined, were given a higher score than they had originally. It's quite possible this trend has led to an improvement in the survival figures that is more apparent than real. All cases of prostate cancer seem more dangerous than previously, so surviving them seems, perhaps, more significant than it really is. Related to this is a possible issue around over-diagnosis and over-treatment of prostate cancer. Clearly all cases must be taken seriously. But it is still true that many men diagnosed with the disease may not require treatment and having such treatment may have an adverse effect on quality of life without bringing real health benefit.

Source
Journal of the National Cancer Institute 7th September 2005 Volume 97 pages 1236-1237

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