Analysis: 5-ARI improves reliability of PSA test

The PSA test appears to be more reliable in men taking dutasteride (Avodart), recent study results indicate.

"Dutasteride stabilizes the amount of PSA that comes from enlarged prostates and low-grade cancers," said lead author Gerald Andriole, MD, of the Washington University School of Medicine in St. Louis. "This enhances a rising PSA’s ability to detect high-grade cancers that require early diagnosis and treatment, while reducing the discovery of tumors that are unlikely to cause harm if left untreated."

In the study, the researchers looked at data from the 4-year Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, which evaluated whether dutasteride, which is currently used to treat BPH, could reduce the risk of detecting prostate cancer in men with an increased risk of the disease. The study involved 8,231 men ages 50 to 75 years who were randomly assigned to receive a placebo or dutasteride, 0.5 mg. The men had elevated PSA levels (2.5 ng/mL-10.0 ng/mL) but no evidence of cancer on biopsies performed within 6 months of enrolling in the trial.

Among men taking dutasteride, the team found that any subsequent rise in PSA levels over the course of the study was more likely to be linked to aggressive, high-grade tumors (Gleason score 7-10), compared with rising PSA levels in men on a placebo.

“If a man is taking dutastride and his PSA level starts to rise, he has a higher chance of having an aggressive cancer,” Dr. Andriole said. “This makes PSA a more effective screening tool for prostate cancer, but even more importantly for aggressive cancer.”

Over 4 years, PSA levels increased in 72% of men taking a placebo and only 29% of men taking dutasteride, the data show. However, there was no significant difference in high-grade tumors between the two groups.

Results of the current study were published in the Journal of Urology (2011; 185:126-31).

The REDUCE trial was supported by GlaxoSmithKline.