Lymphatic micrometastases predict biochemical recurrence in patients undergoing radical prostatectomy and pelvic lymph node dissection for prostate cancer

Background Nodal metastasis is a strong prognostic parameter in prostate cancer (PCa). We analysed the detection of micrometastases (miN + ) in initially nodal-negative (pN0) radical prostatectomy specimens from pT2a-c and pT3a PCa patients by immunohistochemistry (IHC). Material and Methods A total of 2352 lymph nodes of 193 PCa patients were centrally re-examined for miN + or miN- status using IHC. Results were correlated with clinical and follow-up data. Recurrence-free survival (RFS) was calculated with the log-rank test using the Kaplan-Meier method. In addition, a logistic regression analysis was performed. Results IHC detected miN + in a total of 17 patients (8.8 %). miN + seemed to be significantly associated with a higher Gleason score and was detected in more advanced pT stages. A total of 45 patients (23.1 %) had a biochemical recurrence (BCR). BCR was associated with miN +. Patients with miN + had a significantly shorter RFS (22.9 versus 58.7 months; p < 0.001). In the univariate (OR: 5.04; 95 % CI: 2.46 - 10.6; p-value: < 0.0001) and multivariate (OR: 3.29; 95 % CI: 1.54 - 7.08; p-value: 0.002) regression model, the miN + status was the strongest predictor of a BCR. Conclusions IHC seems to be of high diagnostic value for the detection of micrometastases in initially nodal-negative PCa patients. IHC should therefore be performed in PCa patients with nodal-negative findings.