Should Gleason score 7 prostate cancer be considered a unique grade category?

Objectives. To evaluate pathologic characteristics and biochemical survival rate differences between patients with Gleason score 6 or less, 7, and 8 o r more prostate cancer. Methods. A total of 652 patients who underwent a radical prostatectomy for clinically localized prostate cancer between March 1991 and December 1995 w ere selected for this study. Patients who underwent neoadjuvant or adjuvant hormonal therapy or radiotherapy were excluded. Clinical and pathologic da ta were obtained from our prostate cancer data base. Serum prostate-specifi c antigen (PSA) level, pathologic stage, and disease-free survival (DFS) we re analyzed between the three Gleason score groups. Results. The overall mean pretreatment serum PSA level was 12.9 ng/mL, bein g 8.4, 13.4, and 23 ng/mL for Gleason score 6 or less, 7, and 8 or more pro state cancers, respectively (P = 0.0001). Of patients with specimen Gleason score 6 or less, 7, and 8 or more, pathologic organ-confined disease was p resent in 69.4%, 43.1%, and 9.2%, respectively (P = 0.001). Extraprostatic extension was present in 30.6%, 56.9%, and 90.8% (P = 0.0001); positive sur gical margins, considered independently from the other pathologic findings, were present in 31%, 47.6%, and 67.8% of patients with Gleason score 6 or less, 7, and 8 or more, respectively (P = 0.0001). DFS was 34.5% for patien ts with Gleason score 8 or more, 75% for Gleason score 7, and 91.2% for Gle ason score 6 or less prostate cancers, at a median follow-up of 34.2 months (P = 0.0001). On multivariable analysis, after adjusting for serum PSA lev el (10 or less or more than 10 ng/mL) and pathologic stage, Gleason score ( 6 or less, 7, 8 or more) remained a statistically significant predictor of DFS (P = 0.0001). Conclusions. Patients with Gleason score 7 prostate cancer should be consid ered a specific prognostic category. We believe that this distinction is cr itical to obtain more reliable results from prostate cancer analyses about prognosis of patients treated with curative intent. (C) 1999, Elsevier Scie nce Inc. All rights reserved.