Role of Active Surveillance for Localized Small Renal Masses

Context: Stage migration of organ-confined renal masses is occurring as a result of incidental diagnosis, especially in the elderly. Active surveillance (AS) is gaining clinical traction as a treatment alternative to surgery and focal therapy. Objective: To assess contemporary data and evaluate AS risk trade-offs in the treatment of organ-confined kidney cancer. Evidence acquisition: A comprehensive search of the Embase, Medline and Cochrane databases was carried out. A systematic review of the role of AS for organ-confined renal masses was performed. A total of 28 studies were included in the systematic review. Evidence synthesis: The median linear tumor growth rate for clinically localized renal masses (CLRMs) was 0.37 cm/yr (interquartile range 0.15–0.7), with 0.22 cm/yr in the cT1a subgroup and 0.45 cm/yr in the cT1b––2 subgroup. The metastatic progression rate was 1–6% and was similar for cT1a (1–6%) and cT1b (0–5%); other-cause mortality for patients with CLRMs was 0–45% (1–25% for cT1a vs 11–13% for cT1b–2); cancer-specific mortality ranged between 0% and 18%. According to the 2011 Oxford scale, AS as a treatment option for CLRMs remains supported by level 3 evidence. Conclusions: Although no randomized clinical data are available, current data support oncologic safety for AS in the management of CLRMs, particularly for small renal masses and among elderly and/or comorbid patients. Patient summary: In this review we looked at the outcomes for patients with small kidney masses managed with surveillance. We found that surveillance is a safe initial option for tumors of less than 2 cm, especially in elderly and sick patients. Active surveillance for clinically localized renal masses is a safe initial option, especially for masses of <2 cm in elderly and sick patients. Further investigation to establish active surveillance protocols and follow-up are still missing. Prospective nonrandomized registry collection of data for patients with small renal masses is ongoing.