Urine levels of prostate cancer gene 3 (PCA3) correlate with severity of prostate cancer and testing may help select men with low-grade or low-volume disease who would benefit from active surveillance rather than aggressive treatment, according to an article in the May issue of the Journal of Urology.

Researchers at the University of Texas M. D. Anderson Cancer Center, Houston, Texas, evaluated relationships between urinary PCA3 level with tumor volume at prostatectomy and other clinicopathological variables. Urine specimens were collected from 59 men scheduled for biopsy and 83 men scheduled for radical prostatectomy. Findings were evaluable for a total of 96 men.

PCA3 and prostate specific antigen mRNA were quantified with the Gen-Probe DTS 400 System. The PCA3 score was defined as the ratio of PCA3 mRNA/prostate specific antigen mRNA x10.

Researchers found that the PCA3 score in men with negative biopsies (30) and positive biopsies (29) were significantly different (median 21.1 and 31.0, respectively). Furthermore, PCA3 score significantly correlated with total tumor volume in prostatectomy specimens and with prostatectomy Gleason score (6 versus 7 or greater) but not with other clinical and pathological features.

The PCA3 score was significantly different when comparing low volume/low grade cancer (dominant tumor volume less than 0.5 cc, Gleason score 6) and significant cancer. On multivariate analysis PCA3 was the best predictor of total tumor volume in prostatectomy.

Because the PCA3 score appears to stratify men based on prostatectomy tumor volume and Gleason score, the authors concluded it could have clinical applicability in selecting men who would benefit from active surveillance.

"More and more data is emerging that the PCA3 score is a useful measure to fine tune the diagnosis and classification of prostate cancer," said Prof. Ranjan Thilagarajah, Consultant Urological Surgeon at Broomfield Hospital, Mid Essex Health Trust. "PROGENSA PCA3 (the name of the commercial kit) appears to help differentiate between those that are candidates for active surveillance, and those who need aggressive treatments, making it a vital part of cutting-edge prostate cancer management. Here at Broomfield Hospital, we have already used the test in over 100 men, and hope that it will become a useful tool for more men across the country."