Extended biopsy based criteria incorporating cumulative cancer length for predicting clinically insignificant prostate cancer

Abstract

OBJECTIVE • To develop extended biopsy based criteria for predicting insignificant cancer (IC) using extended biopsy findings. PATIENTS AND METHODS • From 2000 to 2009, 1575 patients with prostate cancer were primarily treated by radical prostatectomy in two referral hospitals. • Of these, the study cohort comprised 499 patients with extended biopsy confirmed, clinically organ-confined (cT1 - 2N0M0) prostate cancer with PSA levels of < 20 ng/mL. • Cancer information obtained through extended biopsy included cumulative cancer length (CCL) divided by the number of biopsy cores (CCL/core). RESULTS • Pathological examination revealed 39 ICs (7.8%). All these ICs fell in a category of prostate cancer with clinical stage ≤ T2a and 2005 International Society of Urological Pathology Consensus Conference (ISUP) modified biopsy Gleason score ≤ 7. • Accordingly, we analysed predictors of IC in a subset cohort of 370 patients in this category. A multivariate logistic regression analysis revealed that 2005 ISUP modified biopsy Gleason score and CCL/core were independently significant predictors of IC. • We determined a threshold value of CCL/core of 0.20 mm for predicting IC using receiver operating characteristic analysis. • Based on these findings, we developed simple extended biopsy based criteria for predicting IC as follows: (i) PSA level of < 20 ng/mL; (ii) Clinical stage ≤ T2a; (iii) 2005 ISUP modified biopsy Gleason score ≤ 6; (iv) CCL/core of < 0.20 mm. • The specificity of the criteria was 91%, which was significantly higher than the value from a subset of criteria without item iv ( P < 0.001). CONCLUSION • We have developed extended biopsy based criteria for predicting IC incorporating the 2005 ISUP modified biopsy Gleason score and CCL/core. © 2012 The Authors.