The prognostic significance of tertiary gleason patterns of higher grade in radical prostatectomy specimens - A proposal to modify the Gleason grading system

The Gleason grading system of prostatic adenocarcinoma does not account for the existence of a tertiary (third most prevalent) pattern, and there are no studies concerning the latter's prognostic influence. The authors analyz ed 114 radical prostatectomies with small tertiary components, which mostly occupied less than 5% of whole tumors, These specimens were compared with a prostatectomy database comprised of 2,276 cases without a tertiary compon ent. The pathologic stages of "typical" Gleason score 5 to 6 tumors (Gleaso n scores 2 + 3 = 5,3 + 2 = 5, 3 + 3 = 6), which contained tertiary patterns 4 or 5, were significantly higher than those of "typical" Gleason score 5 to 6 tumors without pattern 4 (p = 0.018) but lower than those of "typical" Gleason score 7 tumors (p = 0.021; Gleason scores, 3 + 4 = 7, 4 + 3 = 7). Typical Gleason score 7 tumors with a tertiary pattern 5 showed significant ly worse pathologic stages than typical Gleason score 7 tumors (p = 0.008) without pattern 5 and were not different statistically from typical Gleason score 8 (Gleason score, 4 + 4 = 8) tumors. Both typical Gleason score 5 to 6 and 7 tumors with tertiary components revealed significantly higher prog ression rates than typical Gleason score 5 to 6 tumors (p <0.0001) and Glea son score 7 tumors (p = 0.003) without tertiary components, and progressed like typical Gleason score 7 and 8 tumors respectively. Tertiary high-grade components have an adverse impact on biologic behavior. The authors propos e that the Gleason system for radical prostatectomy specimens be modified t o take into account small volumes of patterns 4 and 5, which are important prognostically.