Purpose: To our knowledge the extent of lymphadenectomy with cystectomy, the number of lymph nodes to be retrieved and the anatomical groups to be dissected are still undetermined. This study was done to clarify these issues.
Materials and methods: A total of 200 patients underwent radical cystectomy and extended lymphadenectomy up to the level of origin of the inferior mesenteric artery. Removed tissues were labeled according to anatomical location and sent separately for pathological evaluation. In each group the number and status of lymph nodes were determined. The number of positive nodes was correlated with the number of retrieved nodes. Cases with a single positive node were identified and the anatomical location was defined.
Results: The mean number of retrieved nodes per patient +/- SE was 50.6 +/- 14.4 and 48 (24%) patients had nodal disease. The mean number of positive nodes per involved case was 8.08 +/- 13.2. There was a weak correlation between the number of positive nodes and the number of harvested nodes. Bilateral disease was noted in 39.6% of cases. Single node involvement was observed in 22 cases, of which all except 1 were in the endopelvic region.
Conclusions: There is a sentinel region, which is the endopelvic region (that is the internal iliac and obturator groups of lymph nodes). There are no skipped lesions. Negative nodes in the endopelvic region indicate that more proximal dissection is not necessary. Bilateral endopelvic dissection is mandatory.