Factors predicting Gleason score 6 upgrading after radical prostatectomy.

Objective: Prostate cancer Gleason score 6 is the most common score detected on prostatic biopsy. We analyzed the clinical parameters that predict the likelihood of Gleason score upgrading after radical prostatectomy.

Methods: The study population consisted of 241 patients who underwent radical retropubic prostatectomy between Feb 2002 and Dec 2007 for Gleason score 6 adenocarcinoma. The influence of preoperative parameters on the probability of a Gleason score upgrading after surgery was evaluated using multivariate logistic regression and ROC curves.

Results: Gleason score upgrade was found in 92 of 241 patients (38.2%). Multivariate logistic regression analysis showed that only percentage of cancer in dominant lobe and prostate weight were significant predictors for Gleason score upgrading (p = 0.043 and p = 0.006, respectively). ROC curves showed that prostate weight and PSA density were only two independent significant parameters for prediction of upgrade (AUC - 0.634, p <0.0001 and 0.604, p = 0.006, respectively). Gleason score upgrading was observed to be accompanied by significantly higher rates of extra prostatic extension (p <0.001) and seminal vesicle invasion (p = 0.002).

Conclusions: Almost forty percent of tumors graded Gleason 6 at biopsy are Gleason 7 at surgery. Upgraded tumors significantly associated with adverse pathological features. The probability of Gleason score upgrade can be predicted using prostate weight and PSA density as independent parameters.