WASHINGTON (AP) _ New research suggests men who have had prostate cancer treatment may be at dramatically increased risk of eventually dying from the disease if levels of a cancer-linked protein double during the first three months after treatment.
The findings suggest those men need immediate hormone-suppression therapy to try to delay the deadly spread of their returned prostate cancer, and should consider experimental treatments, the researchers reported Tuesday.
Blood levels of a protein called PSA rise as a prostate enlarges or cancer develops. So PSA testing is used to screen men for prostate cancer.
But it's also used to tell if prostate cancer has returned after initial surgical or radiation treatment. How quickly PSA is detected and how rapidly it rises are well-known signals of how aggressive the returning cancer is, and doctors already use them to make treatment decisions. But exactly how those PSA increases correlate with a man's risk of death isn't clear.
Dr. Anthony D'Amico at Brigham and Women's Hospital in Boston tracked 8,669 men after initial prostate cancer treatment. Those whose PSA levels doubled in less than three months were nearly 20 times more likely to eventually die from their cancer than men with slower PSA returns, D'Amico reported Tuesday in the Journal of the National Cancer Institute.
Median survival for the men with the rapid PSA rise was six years, D'Amico said.
In addition to the treatment implications, the finding could prove important for use in studies of possible new cancer therapies, Dr. H.M. Sandler of the University of Michigan wrote in an accompanying editorial. Because prostate cancer takes so many years to kill, scientists have hoped that using PSA levels to predict which drugs might delay death could speed up research on new treatments.
But Sandler cautioned that any use of hormone-suppression therapy can alter PSA's predictive value _ many experimental therapies are offered only when hormones have failed _ so more research ``is urgently required.''
Prostate cancer strikes 220,000 U.S. men annually and kills almost 29,000.