Significance of tertiary Gleason pattern 5 in Gleason score 7 radical prostatectomy specimens.

PURPOSE

The Gleason grading system in reporting prostate cancer accounts for the primary and secondary Gleason pattern. The clinical significance of a higher tertiary (third most prevalent) grade is largely unrecognized.

MATERIALS AND METHODS

Radical prostatectomy specimens from 300 patients with Gleason score 7 (3 + 4 or 4 + 3) prostate cancer were pathologically reexamined for the presence of a tertiary grade 5 pattern as well as the association with pathological stage and biochemical recurrence-free survival.

RESULTS

A total of 214 patients met study inclusion criteria. Patients with Gleason score 7 and tertiary grade 5 cancer had significantly higher pathological stage disease than patients with Gleason score 7 without tertiary grade 5 cancer (p <0.001). Gleason score 7 + tertiary pattern 5 tumors were significantly associated with adverse pathological features such as seminal vesicle invasion, extraprostatic extension and lymphovascular invasion compared to Gleason score 7 tumors (p <0.05). The relative effects of a tertiary grade 5 component on all pathological parameters analyzed was greater for Gleason score 7 tumors with a lower primary Gleason pattern 3 vs a higher primary Gleason pattern 4. Patients with Gleason score 7 + tertiary pattern 5 tumors had significantly decreased biochemical recurrence-free survival (54 months) compared to patients with Gleason score 7 tumors (121 months) (p = 0.0005). Preoperative prostate specific antigen, lymphovascular invasion and positive surgical margin status were shown to be independent predictors of prostate specific antigen recurrence on multivariate analysis.

CONCLUSIONS

Small percentages of tertiary grade 5 patterns in Gleason score 7 radical prostatectomy specimens are associated with aggressive pathological features predictive of advanced pathological stage and biochemical recurrence-free survival.