Prediction of pathological outcomes for a single microfocal (≤3 mm) Gleason 6 prostate cancer detected via contemporary multicore (≥12) biopsy in men with prostate-specific antigen ≤10 ng/mL.

Study Type – Diagnostic (exploratory cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? It has been reported that patients with Gleason 6 prostate cancer detected in a single microfocal positive core may actually harbour more aggressive disease. Meanwhile, several studies analyzing cases of single microfocal prostate cancer included a significant number of patients with serum PSA ≥ 10 ng/mL. Also, significant proportions of currently available published data on actual pathological characteristics of prostate cancer with favourable biopsy features were obtained from patients who underwent prostate biopsies performed in non-systematic fashion at different institutions and/or via non-contemporary scheme, such as sextant biopsy. Although PSA density can be considered an independent predictor of pathologically insignificant tumour among the patients with PSA ≤ 10 ng/mL and only a single microfocal tumour detected via multi (≥12)-core biopsy, clinical and biopsy-related parameters currently available have limited value in predicting pathologically insignificant or unfavourable prostate cancer in such patients. OBJECTIVE • To examine potential predictors of pathological outcomes for a single microfocal (≤3 mm) positive prostate cancer detected via contemporary biopsy scheme in patients presenting with prostate-specific antigen (PSA) ≤10 ng/mL. PATIENTS AND METHODS • We reviewed the data of 119 patients who had prebiopsy PSA ≤ 10 ng/mL and a single microfocal (≤3 mm) Gleason ≤6 prostate cancer identified via multicore (≥12) biopsy and who subsequently underwent radical prostatectomy (RP). • We assessed the rates of insignificant prostate cancer (organ-confined and pathological Gleason ≤6 with tumour volume <0.5 mL) and unfavourable prostate cancer (upstaging and/or upgrading) by analysing pathological findings. • Potential preoperative predictors of insignificant or unfavourable prostate cancer were analysed. Multivariable models for predicting insignificant and unfavourable tumours were devised and evaluated. RESULTS • Overall rates of insignificant and unfavourable prostate cancer were 44.5% and 24.4%, respectively. In multivariate analysis, only PSA density was an independent predictor of insignificant prostate cancer. • Predictive accuracies of multivariable models for predicting insignificant prostate cancer did not exceed 68.2%. No significant predictor for pathologically unfavourable tumour was found in multivariate analysis. • All versions of the multivariable model devised for prediction of unfavourable tumour showed predictive accuracies ≤66.9%. CONCLUSION • Although PSA density can be considered an independent predictor of pathologically insignificant tumour among patients with PSA ≤10 ng/mL and only a single microfocal tumour detected via multicore (≥12) biopsy, the clinical and biopsy-related parameters that are currently available have limited value in predicting pathologically insignificant or unfavourable prostate cancer in such patients.