Tertiary Gleason pattern 5 in Gleason 7 prostate cancer predicts pathological stage and biochemical recurrence.

Abstract

Gleason sum 7 prostate cancers are a heterogeneous group with diverse tumor behaviors and disease outcomes. Tertiary Gleason patterns are reported with increasing frequency, particularly in prostatectomy pathology reports. We studied the pathological and biochemical outcome following radical prostatectomy in men with Gleason sum 7 and tertiary Gleason pattern 5. We reviewed 1,110 cases of clinically localized prostate cancer treated with primary radical prostatectomy between January 1998 and August 2006 through a prospectively collected prostate cancer database. Patients who underwent neoadjuvant or adjuvant hormonal deprivation, radiation or systemic chemotherapy were excluded. Of the 1,110 patients 509 had Gleason sum 7 cancer. Tertiary Gleason pattern was present in 66 of 509 cases (13%) and it was absent in 443 (87%). On multivariate analysis tertiary Gleason pattern 5 was associated with higher pT stage (OR 2.55, 95% CI 1.40-4.65) and biochemical recurrence (HR 1.78, 95% CI 1.00-3.17). On subgroup analysis when patients with Gleason sum 3 + 4 + 5 and 4 + 3 + 5 were compared to their respective referent groups without the tertiary Gleason pattern, the 2 groups showed a trend toward higher pathological stage and prostate specific antigen progression. Patients with Gleason sum 3 + 4 with no tertiary pattern had higher PSA recurrence-free probability than those with Gleason sum 3 + 4 + 5 or 4 + 3 and patients with Gleason sum 4 + 3 + 5 had the lowest PSA recurrence-free probability. In patients with Gleason sum 7 prostate cancer tertiary Gleason grade 5 is significantly associated with higher pT stage and biochemical recurrence. Larger studies are needed to assess the predictive value of tertiary grade compared to other established parameters in predicting the long-term oncological outcome after radical prostatectomy.