Is the apical soft tissue margin a better predictor of biochemical recurrence than the surgical specimen?

To identify predictors of apical surgical margin (ASM) and apical soft tissue margin (ASTM), determine if the ASTM is a better predictor of biochemical recurrence (BR) than the ASM, and ascertain the impact of apical biopsies on BR rates.

One thousand three hundred eight consecutive men underwent open radical retropubic prostatectomy (RP) between October 2000 and December 2006. Circumferential biopsies of the ASTM were obtained intraoperatively and submitted for frozen section analysis. Logistic regression models were utilized to identify the factors associated with the presence of positive ASMs and ASTMs. The estimated 5-year risk of BR was calculated by the Kaplan-Meier method.

Overall, 43 (3.3%) and 86 (6.6%) of cases exhibited positive ASM and ASTM, respectively. ASM was significantly associated with higher mean serum prostate-specific antigen levels, presence of perineural invasion, and greater volume of tumor in the biopsy specimen. None of these factors were observed to be associated with the presence of cancer in the ASTMs. In the multivariate analysis, only the presence of perineural invasion was a significant independent predictor of ASMs. The estimated 5-year BR rates in the positive ASMs only, ASTMs only, and both positive ASMs and ASTMs groups were 48.6%, 4.7%, and 38.8%, respectively.

A positive ASM was associated with a significantly greater risk of BR compared with a positive ASTM. The very low estimated risk of BR at 5 years in cases with ASTM suggests that performing the ASTM biopsies may increase the cure rates achieved with RP.