Background: The Gleason score has been shown to offer important information with regard to prognosis and therapy for patients with adenocarcinoma of the prostate gland. In this study, Gleason scores, as determined by 18-gauge core needle biopsies, were compared with both Gleason scores and the pathological staging of corresponding radical prostatectomy specimens.
Methods: Records of 78 consecutive patients undergoing a radical retropubic prostatectomy between 1998 and 2002 were reviewed. In total, 78 patients were enrolled, all of whom had been diagnosed with adenocarcinoma by transrectal needle biopsies using an 18-gauge automated spring-loaded biopsy gun.
Results: Grading errors were greatest with well-differentiated tumors. The accuracy was 6 (23%) for Gleason scores of 2-4 on needle biopsy. Of the 36 evaluable patients with Gleason scores of 5-7 on needle biopsy, 28 (78%) were graded correctly. All of the Gleason scores of 8-10 on needle biopsy were graded correctly. Eighteen (33%) of 54 patients with a biopsy Gleason score of < 7 had their cancer upgraded to above 7. Tumors in 6 patients (60%) with both a Gleason score < 7 on the needle biopsy and a Gleason score of 7 for the prostatectomy specimen were confined to the prostate.
Conclusion: The potential for grading errors is greatest with well-differentiated tumors and in patients with a Gleason score of < 7 on the needle biopsy. Predictions using Gleason scores are sufficiently accurate to warrant its use with all needle biopsies, recognizing that the potential for grading errors is greatest with well-differentiated tumors.