Prospectively packaged lymph node dissections with radical cystectomy: evaluation of node count variability and node mapping.

PURPOSE: Accumulating evidence supports the relationship between an increased number of lymph nodes (LNs) reported following radical cystectomy (RC) and overall outcome. We prospectively evaluated RC cases with transitional cell carcinoma of the bladder to determine which factors may contribute to the variability in the number of reported LNs.

MATERIALS AND METHODS: We conducted a prospective evaluation in which 144 patients undergoing RC and pelvic lymph node dissection (PLND) between June 2001 and April 2003 were included. Lymph nodes were processed as individual packets. A standard method of evaluating nodal submissions was used. A mixed statistical model was used with neoadjuvant chemotherapy, node status, pathological stage, bacillus Calmette-Guerin exposure, age and number of days from transurethral resection as the fixed effects. Surgeon and pathologist were treated as random effects.

RESULTS: The extended PLND group had a significantly greater lymph node yield (median 22.5 nodes) compared to standard PLND (median 8), however, no staging advantage was observed in the extended dissection group. Only the type of PLND performed was associated with node yield (p <0.001). Subset analysis of patients with unexpected microscopic nodal involvement revealed that 33% had involvement of the common iliac nodes.

CONCLUSIONS: In our series only the extent of the lymph node dissection was found to influence node yield significantly after radical cystectomy. Additionally, the observed risk of involvement of the common iliac chain in microscopically node positive cases suggests a need to include this region as part of the PLND for bladder cancer for cases without grossly involved LNs.