Role of nerve-sparing radical prostatectomy for clinical stage B2 prostate cancer. To examine the role of nerve-sparing radical prostatectomy in patients with clinical stage B2 prostate cancer we reviewed the first 77 such patients in our series since we adopted the nerve-sparing technique. A total of 47 patients (61%) underwent bilateral and 26 (34%) underwent unilateral nerve-sparing prostatectomy, while in 4 (5%) both neurovascular bundles were resected. Among the patients followed for 12 months 27 of 41 (66%) treated with bilateral and 7 of 19 (37%) treated with unilateral nerve-sparing prostatectomy had potency preserved. With the strict clinicopathological criteria of organ-confined tumor, that is intracapsular tumor with negative surgical margins and undetectable postoperative prostate specific antigen levels, complete tumor excision was achieved in 17 patients (36%) treated with bilateral and 7 of 26 (27%) treated with unilateral nerve-sparing prostatectomy. All patients in whom both neurovascular bundles were resected had pathological stage C or D1 disease. Of the 24 patients who had complete tumor excision by the strict criteria only 15 (19.5% of the 77 preoperatively potent patients) had potency preserved. Of these patients 19 had microscopically positive margins without seminal vesicle invasion (pathological stage C1) with undetectable postoperative prostate specific antigen levels. In addition, 4 patients had seminal vesicle involvement with negative surgical margins and undetectable postoperative prostate specific antigen levels. If these patients also are considered as having complete tumor excision, there was an over-all complete tumor excision rate of 61% (47 of 77), of whom 25 (32% of the 77 patients) had preservation of potency. Ten patients with clinical stage B2 tumor whose potency was preserved had histological and serological evidence of incomplete tumor excision. Of 53 patients with pathological stage C1 disease 9 (17%) had margins positive only in the regions of the neurovascular bundles. Preoperative prostate specific antigen and acid phosphatase levels, and findings on transrectal ultrasonography failed to predict accurately which patients had extracapsular tumor extension. Patients with poorly differentiated tumors and/or bulky disease on rectal examination had a higher incidence of extracapsular extension and positive margins. We conclude that in the majority of potent patients with clinical stage B2 prostate cancer not all of the goals of nerve-sparing radical prostatectomy are realized.(ABSTRACT TRUNCATED AT 400 WORDS). 