Outcome of Gleason 3 + 5 = 8 Prostate Cancer Diagnosed on Needle Biopsy: Prognostic Comparison with Gleason 4 + 4 = 8.

PURPOSE: ISUP (International Society for Urologic Pathology) and WHO adopted prognostic Grade Groups 1 to 5 that simplify prostate cancer grading for prognosis. Grade Group 4 is Gleason score 8 cancer, which is heterogeneous, and it encompasses Gleason score 4 + 4 = 8, 3 + 5 = 8 and 5 + 3 = 8. The comparative prognostic implications of these various Gleason scores had not been studied by urological pathologists after a re-review of slides. MATERIALS AND METHODS: Patients with a highest biopsy Gleason score of 3 + 5 = 8 or 4 + 4 = 8 were included in the study. Controls were cases with a highest Gleason score of 4 + 3 = 7 or 9-10. A total of 423 prostatic biopsy cases accessioned from 2005 to 2013 at 2 institutions were reviewed. Clinicopathological findings and followup (median 33.4 months) were assessed. RESULTS: Among Gleason score 8 cancers the cancer status outcome in 51 men with Gleason score 3 + 5 = 8 was marginally worse than in 114 with Gleason score 4 + 4 = 8 (p = 0.04). This was driven by a persistent nonmetastatic (after radiation/hormone therapy) cancer rate of 37% among Gleason score 3 + 5 = 8 cases vs 24% among Gleason score 4 + 4 = 8 cases. Conversely, cancer specific survival at 36-month followup was 97.8% in 3 + 5 cases vs 92.6% in 4 + 4 cases but this was not significant (p = 0.089). Cancer specific survival in the Gleason score 8 group was dichotomized by the presence of cribriform growth (p = 0.018). All Gleason score categories did not differ in the fraction of biopsy cores positive, clinical presentation or pathological findings, including the frequency of Gleason pattern 5, in 70 patients who underwent prostatectomy. CONCLUSIONS: Using the most current standards of prostate cancer grading the prognosis is not different in Gleason score 3 + 5 = 8 and 4 + 4 = 8 cancers. This justifies including both in Grade Group 4.

Average Weight of Seminal Vesicles: An Adjustment Factor for Radical Prostatectomy Specimens Weighed With Seminal Vesicles.

The International Society of Urological Pathology in 2010 recommended weighing prostates without seminal vesicles (SV) to include only prostate weight in prostate-specific antigen (PSA) density (PSAD) calculation, because SV do not produce PSA. Large retrospective cohorts exist with combined weight recorded that needs to be modified for retrospective analysis. Weights of prostates and SV were separately recorded in 172 consecutive prostatectomies. The average weight of SV and proportion of prostate weight from combined weight were calculated. The adjustment factors were then validated on databases of 2 other institutions. The average weight of bilateral SV was 6.4 g (range = 1-17.3 g). The prostate constituted on average 87% (range = 66% to 98%) of the total specimen weight. There was no correlation between patient age and prostate weight with SV weight. The best performing correction method was to subtract 6.4 g from total radical prostatectomy weight and to use this weight for PSAD calculation. The average weights of retrospective specimens weighed with SV were not significantly different between the 3 institutions. Using our data allowed calibration of the weights and PSAD between the cohorts weighed with and without SV. Thus, prostate weight in specimens including SV weight can be adjusted by subtracting 6.4 g, resulting in significant change of PSAD. Some institution-specific variations may exist, which could further increase the precision of retrospective analysis involving prostate weight and PSAD. However, unless institution-specific adjustment parameters are developed, we recommend that this correction factor be used for retrospective cohorts or in institutions where combined weight is still recorded.