Cribriform architecture outperforms Gleason pattern 4 percentage and tertiary Gleason pattern 5 in predicting the outcome of Grade Group 2 prostate cancer patients

AIMS: Gleason pattern 4 (GP4) percentage, invasive cribriform and/or intraductal carcinoma (IC/IDC) and the presence of tertiary Gleason pattern 5 (TP5) in radical prostatectomy (RP) specimens all aid in the risk stratification of Grade Group (GG) 2 prostate cancer patients. However, it is unclear to what extent these pathological features are mutually related and what are their individual values if they are investigated simultaneously. The aims of this study were: (i) to determine the mutual relationships of the GP4 percentage, IC/IDC and TP5 in GG2 RP specimens; and (ii) to assess their prognostic value for biochemical recurrence-free survival (BCRFS). METHODS AND RESULTS: Of 1064 RP specimens, 472 (44.4%) showed GG2 prostate cancer. Patients with ≥25% GP4 more frequently had IC/IDC (67.0% versus 43.9%; P < 0.001) and TP5 (20.6% versus 5.8%; P < 0.001) than those with <25% GP4. In unadjusted analysis, an increased GP4 percentage hazard ratio (HR) 1.3; 95% confidence interval (CI) 1.0-1.6; P = 0.04 and IC/IDC (log rank P < 0.001) were associated with shorter BCRFS, whereas TP5 (P = 0.12) and a dichotomised (<25%, ≥25%) GP4 percentage (P = 0.10) were not. In multivariable analysis, IC/IDC was an independent prognostic factor (HR 1.9; 95% CI 1.2-2.9; P = 0.005) for BCRFS, whereas a continuous or dichotomised GP4 percentage and TP5 were not independent prognostic factors. CONCLUSION: In conclusion, a higher GP4 percentage in RP specimens was associated with more frequent IC/IDC and TP5. IC/IDC was an independent predictor for BCRFS, whereas the GP4 percentage and TP5 were not. These findings underscore the importance of routinely including the presence of IC/IDC in RP pathology reports.