April 26, 2007

Better prostate cancer test

A far more accurate blood test for prostate cancer has been created The American Cancer Society projects that in 2007 there will be 219,000 new cases and 27,000 deaths. Yet detecting the disease early has always been problematic.

The new tests accuracy: about 3 percent of the time, when the test was positive, there was no prostate cancer there. In 6 percent of cases, there were false negatives [meaning the test came out negative but the patient did have cancer].

This compares to the PSA test where 80 percent of the positives turn out negative.
An estimated 1.3 million to 1.6 million men undergo biopsies every year to identify the 230,000 or so patients with cancer.

Widespread adoption of this test could help identify prostate cancer in the early stage when it is relatively easy to successfully treat. Perhaps over 94% of the cases could be identified early.


al fin said...

The new test has better specificity and selectivity than the PSA, but for a universal screening test it's still not perfect. Confirming the screen with prostate biopsy is likewise hit or miss, in early stages.

Treatment for prostate cancer leaves a lot to be desired, so you do not want to undergo treatment unnecessarily.

By the way, the PSA gives a continuous value, rather than a positive or negative. It is possible to improve specificity by looking at the free/total PSA ratio.