Does tumor extent on needle prostatic biopsies influence the value of perineural invasion to predict pathologic stage > T2 in radical prostatectomies?

Purpose: Perineural invasion (PNI) on needle prostatic biopsies (NPB) has been controversial as a marker of extraprostatic extension and consequently for planning of nerve-sparing radical prostatectomy (RP). The aim of this study was to find whether tumor extent on NPB influences the value of PNI to predict stage > pT2 on RP.

Materials And Methods: This retrospective study was based on 264 consecutive patients submitted to radical retropubic prostatectomy. Their NPB were matched with whole-mount processed and totally embedded surgical specimens. Tumor extent on NPB was evaluated as the percentage of linear tissue in mm containing carcinoma in all cores. Considering the median value, patients were stratified into 2 groups: harboring less or more extensive tumors on NPB. Univariate and multivariate logistic regression analyses were used to relate stage > pT2 to PNI and other clinical and pathological variables.

Results: In patients with more extensive tumors, PNI was predictive of stage > pT2 in univariate analysis but not in multivariate analysis. In less extensive tumors, PNI showed no association between any clinical or pathological variables studied; no difference in the time to biochemical progression-free status compared to patients without PNI; and, no predictive value for pathological stage > pT2 on both univariate and multivariate analyses.

Conclusion: Tumor extent on NPB influences the predictive value of PNI for pathologic stage > pT2 on RP. With a higher number of small tumors currently detected, there is no evidence that perineural invasion should influence the decision on preservation of the nerve during radical prostatectomy.