['The incidence of unsuspected lymph node metastasis seems to be decreasing in the prostate-specific antigen (PSA) era. It remains controversial as to whether routine pelvic lymph node dissection and per-operative frozen section examination should be performed. In addition, it is still unclear whether an aggressive approach to local disease by surgery or irradiation confers survival benefits on stage D1 patients.', 'Eighty-eight consecutive patients with clinically localized prostate cancer who underwent pelvic lymph node dissection prior to radical prostatectomy during the period between 1985 and 1998 were analyzed. The incidence of lymph node metastases after 1992 was compared with that before 1992. Sensitivity and specificity of frozen section examination was assessed. Progression-free survival and cause-specific survival curves of node-positive patients who underwent radical prostatectomy were estimated by the Kaplan-Meier method.', 'Six of 17 patients (35.3%) treated before 1992 and five of 71 patients (7.0%) treated after 1992 showed unsuspected lymph node metastasis (P = 0.0059). Eight of 11 node-positive patients underwent radical prostatectomy and two have so far demonstrated clinical progression and cancer death with a median follow-up period of 63 months. The 5 year progression-free rate and the cause-specific survival rate for these patients were 71.4 and 85.7%, respectively. Sensitivity of frozen section examination for micrometastasis and gross-metastasis cases, respectively, was 3/6 (50%) and 4/4 (100%), while specificity was 85/85 (100%).'] Is per-operative frozen section examination of pelvic nodes unnecessary for the majority of clinically localized prostate cancers in the prostate-specific antigen era?