Active surveillance in renal tumors: Clinical and oncological outcomes.

Context: Some patients diagnosed with small renal solid masses or complex cystic lesions may benefit from active surveillance (AS) instead of immediate treatment.

Aims: Report our series of patients undergoing AS for small renal solid and complex cystic lesions, and compare growth rates and outcomes between both types of lesions.

Materials And Methods: A retrospective review AS database for renal lesions was conducted. From 1995 to 2017, a total of 82 patients with 89 renal lesions were included. We describe our AS protocol, patient and tumor characteristics, comparisons between solid and cystic lesions, and final outcome of patients who underwent delayed intervention (DI).

Statistical Analysis Used: Categorical and continuous data were analyzed by the Chi-square and the Student's t-test, respectively. The Wilcoxon/Kruskal-Wallis test was used for growth rate comparisons of solid and complex cystic lesions.

Results: Median age of patients at the beginning of AS was 77-year-old, median size for solid and cystic lesions was 2.3 cm (0.08-3.8) and 2.6 cm (1.2-4.0), respectively. No differences in annual growth rate between solid and complex cystic lesions (0.04 cm [0.00-1.5] and 0.05 cm [0.01-1.7]) were observed at a similar median follow-up of 61 months for both groups (range: 15-182, and 14-254). Five patients with solid lesions underwent DI, 3 for rapid growth (>0.5 cm/year), 1 demanded treatment, and 1 due to hematuria. Adherence to AS protocol was high (94%). No cancer-related deaths or metastatic progression was observed, six patients died of another medical condition, being cardiovascular disease the most frequent cause.

Conclusions: AS is a reasonable and safe option for the management of small renal masses. No difference was observed in the growth rate between solid and complex cystic lesions during AS. Centers offering AS should present a standardized protocol and give exhaustive information to patients regarding benefits and risks.