Evaluation of tumor morphologies and association with biochemical recurrence after radical prostatectomy in grade group 5 prostate cancer.

We assessed Gleason pattern 5 (GP5) and other prostatic adenocarcinoma (PCa) morphologies to determine their association with biochemical recurrence (BCR). A search for grade group 5 PCa with radical prostatectomy (RP) yielded 49 patients. RPs were reviewed for %GP5 and morphologies (sheets, single cells, cords, small solid cylinders, solid medium to large nests with rosette-like spaces [SMLNRS], comedonecrosis, cribriform glands, glomerulations, intraductal carcinoma of the prostate [IDC-P], and prostatic ductal adenocarcinoma [PDCa]). Prevalence of morphologies was as follows: single cells 100%, cribriform glands 98.7%, cords 85.7%, IDC-P 77.6%, comedonecrosis 53.1%, sheets 49.0%, small solid cylinders 49.0%, PDCa 44.9%, glomerulations 34.7%, and SMLNRS 14.3%. From 28 patients who were treated with RP as monotherapy, 64.3% (18/28) had BCR. Comedonecrosis, sheets, small solid cylinders, IDC-P, and PDCa were significantly associated with BCR. Number of morphologies on RP and %GP5 were higher in patients with BCR (6.8 ± 2.1 versus 3.7 ± 2.9%; P < 0.001 and 26.9 ± 16.8 versus 11.4 ± 14.1%; P = 0.02) with area under ROC curve of 0.89 (confidence intervals [CI] 0.77-1.00). Sensitivity/specificity was 77.8/80.0% for predicting BCR when ≥ 5 morphologies were present and 0.79 (CI 0.60-0.99) with sensitivity/specificity of 66.7/80.0% for predicting BCR when ≥ 15% GP5 was present. Hazard ratio for BCR was higher with increasing number of morphologies (1.23, CI 1.02-1.49; P = 0.034) but not %GP5 (0.99, CI 0.97-1.02, P = 0.622). Our results indicate that GP5 morphologies may represent a biologically heterogeneous group and that an increasing number of PCa morphologies on RP is strongly associated with an increased risk of BCR.