The percentage of positive biopsy cores as a predictor of disease recurrence in patients with prostate cancer treated with radical prostatectomy.

OBJECTIVE

To analyse the prognostic value of the percentage of positive biopsy cores (PPBC) in determining the pathological features and biochemical outcome of patients with prostate cancer treated by radical prostatectomy, as published data evaluating the prognostic value of PPBC in such patients have limitations.

PATIENTS AND METHODS

A group of 534 patients with clinically localized prostate cancer was selected. The PPBC was defined as the number of positive biopsy cores/total number of biopsy cores x 100, and grouped into categories of <25%, 25.1-50%, 50.1-75% and 75.1-100%. Patients were divided in low-, intermediate- and high-risk groups according to the usual variables.

RESULTS

The mean follow-up was 60.5 months. PPBC was associated with the preoperative serum prostate-specific antigen (PSA) level, biopsy Gleason score and clinical stage. On multivariate analysis, PPBC was a significant predictor of extraprostatic disease and seminal vesicle involvement. Of patients in the four PPBC categories, 16%, 27%, 33% and 60%, respectively, had biochemical recurrence (P < 0.001), and on Cox regression analysis, PPBC was an independent predictor of disease recurrence. After segregating patients into risk groups the PPBC further stratified patients using thresholds of 75% (P = 0.006), 25% (P = 0.026) and 50% (P = 0.011) for low-, intermediate- and high-risk groups, respectively.

CONCLUSIONS

We confirmed, with a longer follow-up, the clinical utility of the PPBC in determining the pathological features and biochemical outcome of patients with prostate cancer treated with radical prostatectomy, and established thresholds for use in patients in the three risk groups.