Prognostic Significance of Architectural Subtypes of Gleason Grade 4 Prostate Cancer in Radical Prostatectomy: A Semiquantitative Method of Evaluation

Studies have shown that Gleason grade 4 extent as well as architectural subtypes provide prognostic information. We aimed to evaluate the influence on biochemical recurrence following radical prostatectomy of patients with organ-confined tumor, Gleason score 7, and negative surgical margins. Total tumor extent, Gleason grade 4 total extent and the extent of each architectural subtype (fused glands, poorly defined glands, cribriform glands, and glomeruloid glands) were evaluated by a semiquantitative point-count method using different colors to identify each subtype. Microscopic morphology of glomeruloid glands was considered regardless of morphology: size (small or large), attachment (narrow or extensive), and cribriform or solid intraluminal protrusion. Gleason grade 4 total extent significantly predicted shorter time to biochemical recurrence in univariate and multivariate analysis. Stratifying extent, Gleason grade 4 with >30% of the total grade 4 extent was significantly predictive for time of recurrence. Considering architectural subtypes, cribriform and glomeruloid glands but not fused and poorly formed glands extent, significantly predicted shorter time to recurrence in univariate analysis. An important issue related to the studies on prognostic significance of Gleason grade 4 subtypes is the lack of uniformity in the definition of microscopic morphology of the subtypes particularly of the glomeruloid architecture.