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Diagnosing Prostate Cancer Just Got Easier

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A new prostate cancer screening method combines drug therapy and changes in prostate-specific antigen (PSA) levels over time to identify men with a high PSA who are more likely to have aggressive prostate cancer despite negative biopsies.

In a study published in the Journal of Urology, researchers at NewYork-Presbyterian Hospital/Weill Cornell Medical Center show that PSA can be a much more effective marker for prostate cancer when an additional drug therapy is added than when PSA is used as a single test.

“At a time when the value of PSA is being increasingly debated, we have shown that when used in a specific way, it can be of great value in identifying men with previously undetected prostate cancer,” says the study’s lead investigator, Dr Steven A. Kaplan, the E. Darracott Vaughan Jr, Professor of Urology at Weill Cornell Medical College and director of the Iris Cantor Men’s Health Center at NewYork-Presbyterian/Weill Cornell.

“We have shown that using PSA with these drugs can help us differentiate prostate cancer from benign prostate disease in patients who are difficult to diagnose,” says Kaplan, who is also chief of the Institute for Bladder and Prostate Health at NewYork-Presbyterian/Weill Cornell. “It also demonstrates a better way to use both the PSA test and these powerful drugs.”

The research team set out to determine the effects of two 5-alpha-reductase inhibitor drugs (finasteride and dutasteride) on PSA levels. The team’s theory was that these drugs, which are designed to reduce the size of an enlarged prostate, might improve the usefulness of PSA in diagnosing prostate cancer. For example, if PSA levels remain persistently high after the prostate has shrunk, or if PSA levels rise after reaching its lowest level, it could indicate the presence of cancer. And, according to researchers, when the prostate gland is smaller, a biopsy can be more effective.

Conducted in 2 phases, the study enrolled 276 men at NewYork-Presbyterian/Weill Cornell who had a normal digital rectal examination, a PSA greater than 4, and 2 or more negative biopsies.

In the first phase of the study, 97 patients were given 5 mg of finasteride or 0.5 mg of dutasteride daily. Their PSA was assessed at 6 and 12 months. Then, a transrectal ultrasonography and a biopsy were completed at 1 year. Study results show that a year of the drug therapy reduced PSA in all the men by an average of 48%. However, the extent of reduction was significantly greater in men with benign prostate disease and significantly less in the 28% of the patients whose prostate biopsy detected cancer.

In the second phase, 179 patients received the same drug therapy but received a biopsy only if their PSA showed a change of 0.4 ng/dL. This meant that men who didn’t need a biopsy did not have one, unlike all the men in phase 1. Results show a biopsy was performed on 42 men (27%), and 26 of those participants (54%) had cancer. Within that group, 77% of the patients had high-grade tumors.

“Our study shows these drugs may be most helpful in helping us diagnose undetectable prostate cancer,” Kaplan says.

Source: Weill Cornell Medical Center.