Evaluation of the 7th American Joint Committee on Cancer TNM Staging System for Prostate Cancer in Point of Classification of Bladder Neck Invasion

Abstract

To assess the validity of the 7th edition of the American Joint Committee on Cancer TNM staging system for prostate cancer, paying special attention to bladder neck invasion, in an Asian population. Clinicopathologic data of 368 men who underwent radical prostatectomy between 2003 and 2011 at our institution were reviewed. The main interest of this study was to confirm that both isolated positive bladder neck margin and positive bladder neck margin associated with other surgical margin have more favorable biochemical outcomes than seminal vesicle invasion (pT3b). The 3-year biochemical recurrence-free survival for men with organ confined disease, extraprostatic extension, isolated positive bladder neck margin, positive bladder neck margin with other surgical margin and seminal vesicle invasion was 88.9, 74.8, 51.2, 19.4 and 18.8%, respectively. On multivariate analysis, the increased risk of progression associated with an isolated positive bladder neck margin (hazard ratio 4.34, 95% confidence interval 1.40-13.46, P = 0.011) was less than that of seminal vesicle invasion (hazard ratio 9.67, 95% confidence interval 3.70-25.25, P < 0.001). As for the positive bladder neck margin with other surgical margin, the increased risk of progression (hazard ratio 9.32, 95% confidence interval 3.50-24.82, P < 0.001) was similar to that of men with seminal vesicle invasion. In our study, men with isolated positive bladder neck margin and positive bladder neck margin plus other surgical margin had no worse biochemical outcomes than those with seminal vesicle invasion (pT3b). It is reasonable to classify prostate cancer with bladder neck invasion (the 6th American Joint Committee on Cancer edition pT4 category) into the 7th edition pT3 category.