Developments in kidney tumor nephrometry.

With the widespread use of computed tomography imaging, the majority of renal tumors are currently detected incidentally at lower grade and stage. Partial nephrectomy has become the preferred treatment for many of these smaller, lower-stage, organ-confined tumors. Compared with radical nephrectomy, partial nephrectomy is more technically difficult to perform. Specific tumor features such as tumor size, depth, location, and proximity to the kidney vasculature and urinary collecting system affect the difficulty of resection. Classically, feasibility of resection has been determined subjectively. Recently, 3 methodologies have been proposed to provide standard, more objective preoperative assessment of tumor anatomy. These "nephrometry" systems include the R.E.N.A.L., PADUA, and C-index systems. In this article, we review aspects of each of these systems, their similarities and differences, and their relevance to clinical practice and academic reporting.