Objectives: In the American Joint Committee on Cancer (AJCC) TNM staging system, prostate cancer involving the bladder neck after radical prostatectomy is considered pT4 disease, suggesting a high risk of recurrence. The recurrence risk with pathologic invasion of the bladder neck, however, has not been definitively compared with that associated with extra-organ disease. We therefore compared the recurrence risk in cases with bladder neck involvement with that of cases with extraprostatic extension and/or seminal vesicle invasion.
Methods: The study cohort was composed of 1123 men with clinically localized prostate cancer treated with prostatectomy as monotherapy. The preoperative prostate-specific antigen (PSA) level, bladder neck involvement, margin positivity, Gleason score, and other pathologic categories were assessed as covariates contributing to the PSA-recurrence risk in univariate and multivariable models.
Results: Bladder neck involvement was found in 60 (5%) of 1123 cases. In univariate analysis, the bladder neck was the site-specific margin with the greatest PSA-recurrence risk of focal involvement (relative risk 1.52, 95% confidence interval [CI] 1.15 to 2.00, P = 0.0030). The PSA-recurrence relative risk with extraprostatic extension was 3.05 (95% CI 2.13 to 4.38, P <0.0001) and with seminal vesicle invasion was 8.59 (95% CI 5.76 to 12.82, P <0.0001). In the multivariable model, the PSA-recurrence risk with bladder neck involvement (relative risk 1.19, 95% CI 0.72 to 1.96, P = 0.5) was not a significant independent prognostic factor. Extraprostatic extension (relative risk 2.25, 95% CI 1.54 to 3.27, P <0.0001) and seminal vesicle invasion (relative risk 4.12, 95% CI 2.57 to 6.62, P <0.0001) were significant independent predictors of PSA recurrence.
Conclusions: Any staging system should be evidence based. The current AJCC system for staging bladder neck involvement, however, is contrary to the available evidence. Reclassification of bladder neck involvement as part of the pT3 category should be considered.