Staging of renal cell carcinoma: Past, present, and future

Tumor stage, which describes the anatomic extent of disease, is a powerful determinant of prognosis and survival for patients with renal cell carcinoma (RCC). Stratification of patients based on prognostic outcomes derived from staging systems facilitates therapeutic decision-making, disease surveillance, and clinical research. Staging for RCC has evolved from the Robson classification into the TNM system, developed by the International Union Against Cancer and the American Joint Committee on Cancer. The most recent revisions of the TNM system for RCC introduced in 1997 and 2002 further subdivided organ-confined tumors, reclassified tumors with venous involvement, and clarified the staging of tumors that invade the perisinus fat. Most studies suggest that these revisions have substantially improved prognostication for RCC. Nevertheless, additional modifications have been proposed that would alter the subclassification of organ-confined disease, integrate various levels of venous involvement with other aspects of local tumor aggressiveness, and upgrade the classification of adrenal involvement. The data in support of each of these proposals will be discussed, and the current limitations of clinical and radiographic staging for RCC will be reviewed. Finally, a glimpse into the future of staging of RCC will be offered with a discussion of integrated staging and prognostic systems.