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medpundit |
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Monday, September 13, 2004"The PSA era is over," said researchers at Stanford University school of medicine in their paper in the Journal of Urology. The team studied prostate tissues collected over 20 years, from the time it first became standard to remove prostates in response to high PSA levels. Thomas Stamey, who led the research, said they concluded that the test indicated nothing more than the size of the prostate gland. "Our study raises a very serious question of whether a man should even use the PSA test for prostate cancer screening any more," he said. The original research isn't available on line (at least not for free), but Stanford University gives some details in its press release: To figure out the PSA test’s usefulness in determining which cancers warrant radiation or surgery, Stamey and his team from Stanford’s Department of Urology set out to document what was actually found following prostate removal, such as the volume and the grade of the cancer – two indications of the cancer’s severity. They then compared those findings to aspects that could be determined prior to surgery, such as how many of the cancers could be felt by rectal examination and the patient’s blood PSA level. For the study, they used prostate tissue samples collected by professor John McNeal, MD, who has examined more than 1,300 prostates removed by different urologists at Stanford in the last 20 years. The researchers divided McNeal’s data into four five-year periods between 1983 and 2004 and looked at the characteristics of each cancer. They found that over time, there was a substantial decrease in the correlation between PSA levels and the amount of prostate cancer – from 43 percent predictive ability in the first five-year group down to 2 percent in the most recent one. However, the Stanford researchers concluded that the PSA test is quite accurate at indicating the size of the prostate gland, meaning that it is a direct measure of benign prostatic hyperplasia. And Stamey pointed out that it is still very useful for monitoring patients following prostate removal as an indicator of residual prostate cancer that has spread to other parts of the body. In other words, the test's predictive value was higher years ago when prostate cancers were much larger. But now, we intervene so early in prostate cancer that the PSA has very little correlation between the severity of the cancer (which is not necessarily related to its size) that it isn't useful at all in predicting who will have invasive cancer and who will not. We knew this, but it's nice to have the proof. Now, where can this guy go to get back his idealism? posted by Sydney on 9/13/2004 08:11:00 AM 0 comments 0 Comments: |
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