Prognostic significance of Gleason pattern in patients with Gleason score 7 prostate carcinoma

BACKGROUND: In the current study, the authors sought to further stratify the prognosis of patients with Gleason score (GS) 7 prostate carcinoma. They assessed the influence on outcome of a predominant poorly differentiated Gleason pattern (primary Gleason pattern [GP] 4) and/or a coincident small focus of poorly differentiated tumor of higher grade (tertiary GP 5). METHODS: The authors studied 412 patients (mean postoperative follow-up, 33 months) with GS 7 tumors treated with radical prostatectomy at a single Australian campus between November 1989 and December 2002. The chi-square test, Kaplan-Meier method, and Cox proportional hazards analyses were used to evaluate the correlation between primary GP 4 and tertiary GP 5 with the occurrence of adverse pathologic features and disease recurrence. RESULTS: In this cohort, 307 patients (75%) had primary GP 3 tumors, 105 (25%) had primary GP 4 tumors, and 17 (2.3%) had a tertiary element of high-grade tumor (GP 5). Patients with primary GP 4 tumors displayed higher rates of seminal vesicle involvement and extraprostatic extension and, along with patients with tertiary GP 5, had significantly shorter times to disease recurrence. Univariate analysis demonstrated that primary GP 4 (P = 0.0003) and tertiary GP 5 (P < 0.0001) were strong predictors of disease recurrence. Primary GP 4 (P = 0.0122) remained an independent predictor of disease recurrence on stepwise multivariate analysis. CONCLUSIONS: Primary GP 4 tumors represented an aggressive subset of GS 7 prostate carcinomas. Primary GP was an easily accessible and clinically relevant predictor of disease recurrence in patients with GS 7 prostate carcinoma.