Prognostic significance of microscopic bladder neck invasion in prostate cancer

To assess the prognostic significance of microscopic bladder neck invasion (BNI+) after radical prostatectomy (RP).

From January 1988 to December 2006, 1480 patients with clinically localized prostate cancer were surgically treated at one tertiary university hospital. The risk of biochemical progression, defined as a prostate-specific antigen (PSA) level after RP of >0.2 ng/mL, was assessed with univariate and multivariate analyses for clinical and pathological variables. We compared the biochemical progression-free survival (bPFS) of patients with BNI+ vs stages pT2, pT3a, pT3b and positive lymph nodes (N+). In a second analysis, we evaluated the bPFS of patients in different stages associated with BNI+ and compared them with those in the same stages with no BNI.

BNI+ was found in 132 (9%) patients; the 5-year bPFS was 86%, 54%, 26% and 10% for stages pT2, pT3a, pT3b and N+, respectively, while it was 30% for BNI+ (P < 0.001). There was no difference in the 5-year bPFS between stage pT2 and pT2 + BNI (P = 0.32). Stages pT3a and pT3b had a better 5-year bPFS than stage pT3a + BNI (P = 0.003) and pT3b + BNI (P = 0.001), respectively. In the univariate analysis all variables were associated with BP. In the multivariate analysis, only BNI+ had no association with BP (odds ratio 1.14, 95% confidence interval 0.70-1.85; P = 0.59).

Microscopic BNI+ in prostate cancer is not an independent risk factor for biochemical progression and should be regarded as a factor that worsens the prognosis of the underlying tumour stage. A longer follow-up is necessary to confirm these findings.