The influence of serial sections, immunohistochemistry, and extension of pelvic lymph node dissection on the lymph node status in clinically localized prostate cancer

Abstract

Objectives: Pelvic lymph node metastases indicate a poor prognosis for patients with clinically localized prostate cancer. The aim of the study was to investigate the value of extended histopathological techniques considering the extent of pelvic lymphadenectomy and preoperative risk factors.

Methods: Total of 194 patients with prostate cancer were examined. At first all patients had a sampling of the sentinel lymph nodes (SLN) followed in most cases by a modified or extended pelvic lymphadenectomy. Step sections, serial sections and immunohistochemistry (IHC, pancytokeratin antibody) were analyzed in all SLN and so-called non-SLN of the first 100 patients. Later serial sections and IHC of non-SLN were left out.

Results: In 26.8% lymphatic metastases were found. The detection rate of lymph node-positive patients depend significantly on the chosen extension of pelvic lymphadenectomy. Limiting the histopathological investigation to the lymph node specimen of the obturator fossa only 44.2% of lymph node-positive cases would have been identified. An additional inclusion of all lymph nodes surrounding the external iliac vessels improves the sensitivity to 65.4% (46.7% and 73.3% for the first 100 patients). Compared to the extension of pelvic lymphadenectomy the diagnostic gain of serial section and IHC (13.8% versus 53.3%) was comparably low.

Conclusions: The extension of pelvic lymph node dissection is of outstanding value for the identification of node-positive patients. Limiting the number of lymph nodes to the ones with the highest probability of bearing lymphatic spread (SLN) makes the use of extensive histopathological techniques more feasible.