Level of invasion into fibromuscular band is an independent factor for positive surgical margin and biochemical recurrence in men with organ confined prostate cancer.

BACKGROUND: This study aimed investigate the effect of the level of invasion into fibromuscular band (FMB) of prostate on the positive surgical margin (PSM) and biochemical recurrence (BCR) after radical prostatectomy (RP) in patients with organ-confined (pT2) prostate cancer.

METHODS: The clinical and pathological data of 461 consecutive patients with pT2 prostate cancer were evaluated regarding the level of invasion into FMB. The relationship between levels of invasion into FMB and PSM / BCR was assessed.

RESULTS: The rate of PSM at an FMB level of at 2 was 18.8%, which was significantly greater than the rates at levels 0 (5.4%) and 1 (7.8%). The level of FMB (p = 0.007) and percentage of tumor volume (p = 0.012) were identified as independent factors predictive of a positive surgical margin in a multivariate analysis. The 5-year BCR-free survival rates for a level 0-1 FMB with negative surgical margin, level 0-1 FMB with positive surgical margin, level 2 FMB with negative surgical margin, and level 2 FMB with positive surgical margin were 96.6%, 86.4%, 85.6%, and 72.9%, respectively (p <  0.001). A level 2 FMB (p = 0.050), positive surgical margin (p = 0.001), and surgical Gleason score (p = 0.001) were identified as independent predictors of a BCR of pT2 prostate cancer.

CONCLUSIONS: Among patients with negative surgical margins, the surgical Gleason score and level of FMB independently affected the incidence of a BCR of pT2 prostate cancer. The level of FMB was an independent predictor of both a positive surgical margin and a BCR of pT2 disease. Accordingly, the level of FMB might help to further stratify the prognosis of patients with pT2 disease.