Objective: To report experience with sentinel node (SN) lymphadenectomy which allows an assessment of the exact location of radioactive and of tumour-bearing lymph nodes, and evaluate differences in timing of the scintigraphy and surgery.
Patients and methods: The study included 35 patients who opted for external beam radiation therapy for prostate carcinoma of intermediate or poor prognosis. Agreement was reached between the participating urologists and the physicians of the nuclear medicine department on the definition of the relevant anatomical areas. The time between a transrectal intraprostatic injection with the radioactive nanocolloid and the laparoscopic SN procedure varied from 5 h to 26 h. Scintigrams were merged with the computed tomography scans until combined methods became available. A laparoscopic gamma-probe was used to identification the SNs, and an extensive laparoscopic node dissection undertaken in the same procedure. Lymph nodes were submitted to the pathologist in such a way that their exact location could be reconstructed. After surgery a graphic report was produced showing the exact location of the lymph nodes.
Results: Of the 35 patients 40% were node positive; a mean of 13.5 nodes were resected, and there were no false-negative results. The location of the vast majority of the tumour-positive SNs was around the bifurcation of the external and internal iliac artery, and so involved nodes from the internal iliac, external iliac, communis and obturator basins. Of the six SNs outside the extended node dissection area, two were positive but only one of them exclusively so (lateral to the external iliac artery). The scintigrams did not change after 4 h, and the operation should be done within 24 h to have sufficient radioactivity in the nodes to be detected by the probe. There were eight complications (23%) but only one could be attributed to the SN procedure; the others were thought to be related to the extended laparoscopic node dissection.
Conclusion: The laparoscopic SN procedure is a reliable tool for diagnosing prostate cancer-bearing lymph nodes, but the extended laparoscopic node dissection has, in this series and others, too many complications for it to be attractive for diagnostic purposes. The SN procedure makes an extended node dissection unnecessary in most patients.