PSA Plus Drug Therapy Helps Diagnose Prostate Cancer Better

PSA can be a much more effective marker for prostate cancer when additional drug therapy is used than it can as a stand-alone test, which is how physicians currently use it.

The new prostate cancer screening method uses the combination of drug therapy and changes in PSA levels over time to identify men with a high PSA who are more likely to have aggressive prostate cancer despite negative biopsies.

"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," said the study’s lead investigator, Prof. Steven A. Kaplan, the E. Darracott Vaughan Jr., professor of Urology at Weill Cornell Medical College (New York, NY, USA) and director of the Iris Cantor Men's Health Center at NewYork-Presbyterian/Weill Cornell (New York, NY, USA).

Prof. Kaplan created the combination screening method as a way to understand cancer risk in men who have consistently abnormal PSA readings despite one or more negative biopsies. This patient population offers physicians a diagnostic dilemma, Prof. Kaplan said, “Despite the fact that biopsies are becoming more and more effective at detecting cancer in the prostate, a significant number of patients with prostate cancer continue to have negative biopsies.”

He added that the PSA (prostate specific antigen) test alone is not a good indicator of prostate cancer; "It measures multiple factors associated with prostate disease, including enlargement of the prostate and inflammation."

The study was conducted in two phases: it enrolled 276 men at NewYork-Presbyterian/Weill Cornell whose PSA was greater than four, who had a normal digital rectal examination and two or more negative biopsies.

In the first phase, 97 patients, who were given 5 milligrams of finasteride or 0.5 milligrams of dutasteride daily, had their PSA measured at 6 and 12 months, a transrectal ultrasonography and a biopsy performed at 1 year. Study results show that a year of the drug therapy reduced PSA in all the men—an average of 48 %—but the magnitude of reduction was significantly greater in men with benign prostate disease and significantly less in 28 % of the patients whose prostate biopsy detected cancer.

In the second phase of the study, 179 patients received the same drug therapy but underwent a biopsy only if their PSA showed a change of 0.4 ng/dL. Forty-two men (27 percent) had the biopsy, and 26 of those participants (54 percent) had cancer. Within that group, 77 % of the patients had high-grade tumors.

Cancer cases in men, who participated in the second phase study with the combined drug therapy and evaluation of PSA trends, were identified by sending those with minimal changes for a biopsy. This meant that men who did not need a biopsy did not have one––unlike all the men in phase one.

"Our study shows these drugs may be most helpful in helping us diagnose undetectable prostate cancer," Prof. Kaplan said.

Related Links:
Weill Cornell Medical College
Iris Cantor Men's Health Center at NewYork-Presbyterian/Weill Cornell