Comparing the Gleason prostate biopsy and Gleason prostatectomy grading system: the Lahey Clinic Medical Center experience and an international meta-analysis

Abstract

Background: The accuracy of the prostate biopsy Gleason grade to predict the prostatectomy Gleason grade varies tremendously in the literature.

Objectives: Determine the accuracy and distribution of the prostate biopsy Gleason grade and prostatectomy Gleason grade at LCMC (Lahey Clinic Medical Center) and worldwide.

Design, setting, and participants: Participants included 2890 patients who had not received preoperative hormones, and for whom preoperative and postoperative Gleason sums were available. Participants underwent radical prostatectomy at LCMC, an academic referral center, from 1982-2007. Studies for the meta-analysis were selected from Medline: 1994-2007. Search criteria included keywords "Gleason," "biopsy," and "prostatectomy," >/=200 patients, and whether the biopsy and prostatectomy Gleason scores categorized into the predefined Gleason grades. The meta-analysis included 15 studies and the LCMC database for 14,839 total patients.

Measurements: Gleason scores 2-6, 7, and 8-10 were converted to low, moderate, and high grade, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated. The kappa statistic and chi-square were used to compare biopsy and prostatectomy grades.

Results and limitations: The percentage of patients in whom the prostatectomy grade was accurately predicted, upgraded, and downgraded was 58%, 36%, and 5% at LCMC and 63%, 30%, and 7% in the meta-analysis, respectively. The PPV for low-, moderate-, and high-grade cancer was 54%, 70%, and 60% for LCMC and 62%, 70%, and 50% for the meta-analysis, respectively. The sensitivity decreased with increasing Gleason grade (low, moderate, and high) for LCMC (91%, 38%, 28%) and the meta-analysis (90%, 40%, 33%), respectively. The distribution of low-, moderate-, and high-grade cancer on biopsy (69%, 25%, and 6%) and prostatectomy specimen (47%, 44%, and 9%) demonstrated only "fair" agreement (kappa, 0.37).

Conclusions: Patients and practitioners need to be cognizant of significant upgrading for low-grade disease and the downgrading for high-grade disease.