Do Subgroup Evaluations Provide Additional Contributions to Biochemical Recurrence in Grade Group 4 and 5 Patients? A Multicenter Study by the Turkish Urooncology Association Prostate Cancer Working Group

Objective: To investigate the effect of the International Society of Urological Pathology (ISUP) grade group 4 (GG4) and ISUP GG5 subgroups according to prostate biopsy on biochemical recurrence (BCR). Materials and Methods: Patients who underwent radical prostatectomy (RP) after being diagnosed with GG4 and GG5 prostate cancer according to prostate biopsy and who had follow-up data were retrospectively evaluated. Patient data were obtained from the Urologic Cancer Database-Prostate of the Turkish Urooncology Association. GG4 and GG5 pathologies were evaluated using Gleason subgroups. The effect of clinicopathological parameters on BCR after RP was investigated separately in the GG4 and GG5 patient groups. Results: In GG4, 73 of 188 patients developed BCR. When GG4 patients were evaluated for BCR, only lymphovascular invasion was significant for BCR (p=0.004). In addition, seminal vesicle invasion (SVI) and high ISUP grade according to RP pathology were significant in patients with BCR (p=0.004 and p=0.005). In the follow-up of 145 patients with GG5, 80 patients developed BCR. When GG5 patients were evaluated for BCR, no predictive factor was found for developing BCR. However, surgical margin positivity, extraprostatic extension, and SVI after RP were found to be significant in patients with BCR (p=0.031, p=0.011 and p=0.007). Conclusion: According to our results, the ISUP GG system, which does not include Gleason subgroups, is an appropriate classification system for GG4 and GG5 patients for the prediction of BCR in the Turkish patient population, in parallel with the current literature.