Excision of the neurovascular bundle at radical prostatectomy in cases with perineural invasion on needle biopsy

Objectives. To assess, in a group of patients who had undergone radical prostatectomy and who were likely to have extraprostatic extension of their tumors based on the previous finding of perineural invasion on needle biopsy, how effective excision of the neurovascular bundle was in reducing the number of positive margins and increasing the potential cure rate. Methods. Eighty radical prostatectomy cases from our institution that had perineural invasion on prostate needle biopsy were retrospectively studied to determine the presence and location of extraprostatic extension, positive margins, and seminal vesicle or lymph node involvement, whether the neurovascular bundle had been excised, and whether tumor was present in the bundle region. Results. In 14 (17.5%) of 80 cases, excising the neurovascular bundle led to a situation in which there was tumor in the neurovascular bundle, all the surgical margins of resection were negative for tumor, and there was no seminal vesicle or lymph node involvement. The remaining cases were equally divided between (a) less aggressive tumors that were organ-confined or had only focal extraprostatic extension with no tumor in the neurovascular bundle and (b) more aggressive tumors that had positive margins or involvement of the seminal vesicles or lymph nodes. Within the latter group, however, there were 9 patients (11.3% of all 80 cases) with negative seminal vesicles and lymph nodes in whom excision of the neurovascular bundle at least reduced the extent of positive margins. Most of the positive margins in patients with tumor in the neurovascular bundle occurred outside the bundle region, and in this study, none of the cases with positive surgical margins were the sole result of failure to excise the neurovascular bundle. Conclusions. When perineural invasion is seen on needle biopsy, the morbidity of resecting one or both neurovascular bundles, which in some cases could turn out to be unnecessary, must be weighed against the benefit of reducing the incidence of positive margins (17.5% of our cases) or decreasing the extent of positive margins (11.3% of our cases). (C) 1999, Elsevier Science Inc. All rights reserved.