Lymph node dissection for bladder cancer: the issue of extent and feasibility in the minimally invasive era

Lymph node dissection in bladder cancer is an integral part of radical cystectomy. It allows for accurate staging of the patient and will, therefore, serve to dictate additional treatment and add prognostic information. The issue of what is an adequate lymphadenectomy as to the extent and boundaries of the operation, specifically the cephalad extent, has been the focus of recent debate. Some have suggested that lymph node yield, in terms of number, could serve as a surrogate for the adequacy of the node dissection and, thus, the oncologic efficacy of the operation. It has also been suggested that it is a marker for the experience of the operating surgeon. What is meant by a limited, standard and extended lymph node dissection varies among different publications. Recent evidence suggests that an 'extended' node dissection infers oncologic efficacy. With the advent of minimally invasive and, specifically, robotic-assisted surgery, more cystectomies are approached robotically. As such, there has been recent debate as to whether a robotic-assisted procedure can emulate the open approach, satisfying the accepted boundaries and extent of dissection and ultimately leading to equivalent oncologic outcomes without increasing morbidity. In this review, we focus on the extent of lymphadenectomy in bladder cancer by reviewing the lymphatic drainage and arguments in favor of a more extended dissection. We will then address the minimally invasive techniques, focusing on robotic-assisted surgery, and review the evidence suggesting that this is a promising new technique that results in acceptable nodal yield and potentially equivalent oncologic outcomes with no added morbidity.