The role and extent of pelvic lymphadenectomy in the management of patients with invasive urothelial carcinoma.

Lymph node metastases are the most important prognostic variable in determining outcome following radical cystectomy. An anatomic bilateral node dissection includes at a minimum the external and internal iliac and obturator lymph nodes. An extended node dissection may include the distal aortic and vena caval nodes, bilateral common iliac, and pre-sacral nodes, which receive direct lymphatic drainage from the posterior bladder and trigone. This approach sets up the cystectomy, maximizes sensitivity for detection of nodal metastasis, assures optimum local pelvic cancer control, and accurately identifies those high-risk patients with node metastases who may benefit from adjuvant chemotherapy. Lymph node retrieval is affected by several variables of node specimens addition to the anatomic extent of the node dissection. These include presentation to the pathologist in packets, specimen processing and what the pathologist calls a lymph node, and patient age. The current TNM staging system accounts for the number and size of node metastases and may be improved by incorporating lymph node density, which is a composite variable incorporating the number of positive nodes and number of nodes retrieved--a possible surrogate for the extent of the node dissection. Innovations in imaging including novel MRI contrast agents and lymphoscintigraphy may improve the pre-treatment and intra-operative identification of node metastases and lymphatic anatomy. Minimally invasive surgical techniques including robotic-assisted laparoscopic cystectomy may improve peri-operative outcomes but must meet the standard of anatomic node dissection and long-term cancer control afforded by the gold standard of anatomic radical cystectomy and bilateral pelvic and iliac node dissection.