The role of lymph node density in bladder cancer prognostication

Pelvic lymph node metastases from bladder cancer occur in about 25% of patients undergoing radical cystectomy. While the majority of patients with lymph node metastases will develop progressive disease, some patients do exhibit long-term survival with and without adjuvant chemotherapy. The concept of lymph node density has been proposed as a means to stratify patient prognosis since it takes into account two important factors—the number of positive nodes (tumor burden) and the total number of nodes removed/examined (extent of dissection). Due to the lack of agreement on the extent of lymphadenectomy, lymph node density facilitates standardization of lymph node staging, thus allowing for adjuvant therapies and clinical trials to be more uniformly applied. Whether lymph node density provides improved prognostication over the standard nodal staging or absolute number of positive lymph nodes remains controversial. We review the literature regarding the role of lymph node density in the prognostic stratification of node-positive bladder cancer.