Perineural invasion in prostate cancer biopsies is not associated with higher rates of positive surgical margins

Purpose: High rates of extracapsular tumor extension have been reported with biopsy perineural invasion (PNI), leading some to advocate routine resection of the ipsilateral neurovascular bundle (NVB) with radical retropubic prostatectomy (RRP) to assure negative surgical margins. The contemporary rates of extracapsular tumor extension (ECE) and margin status associated with biopsy PNI were investigated.

Materials and methods: The prostate needle biopsies, RRP specimens, and operative reports of 452 consecutive patients undergoing RRP by a single surgeon were reviewed to determine the presence of PNI invasion, presence of ECE, margin status, and preservation of NVB. Patients were excluded from the analysis if they underwent preoperative hormonal ablation or if their original biopsy was not reviewed by the pathologists at our institution. Both univariate and multivariate analyses were performed to determine the effect of PNI on extracapsular extension, the likelihood of performing a bilateral nerve-sparing technique, and the result of a positive surgical margin.

Results: In the 402 evaluable cases, based on multivariate models PNI showed only a marginal association with positive surgical margin (+SM) (P = 0.10) and bilateral nerve-sparing (B-NS) (P = 0.07), but was significantly associated with organ confinement (P = 0.03). The odds ratio (OR) of PNI for +SM, although not statistically significant, was 0.36. Although showing a higher level of statistical significance, PNI for OC had an odds ratio of 0.50. Similarly, the odds ratio was 0.54 for B-NS.

Conclusions: Although biopsy PNI alone was associated with a higher probability of ECE, it is not predictive of bilateral nerve-sparing technique or a positive surgical margin in an individual patient.