Multicenter study of active surveillance for small renal masses: Real world practice pattern

Area of Science:

• Urology
• Oncology
• Nephrology

Background:

• Active surveillance (AS) is a recognized safe strategy for managing small renal masses (SRM) potentially indicative of renal cell carcinoma.
• Real-world outcomes of AS for SRMs were analyzed across five tertiary Spanish centers.

Purpose of the Study:

• To assess clinical, radiological, and pathological characteristics of SRMs under AS.
• To evaluate therapeutic options and oncological outcomes for SRMs managed with AS.
• To identify predictors of deferred intervention (DI) in patients with SRMs on AS.

Main Methods:

• A multicenter retrospective review included 384 patients on AS from January 2012 to September 2024.
• Analysis focused on AS indications, initial lesion size, growth rate (GR), and progression.
• Cox regression analysis identified factors influencing DI, with a mean follow-up of 43 months.

Main Results:

• The average GR was 1.4 mm/y; 15% of patients underwent active treatment.
• Age, tumor size, and tumor growth correlated with DI; initial size correlated with GR.
• High-grade clear cell carcinoma was more frequent in fast-growing lesions (>5 mm/y GR) compared to slow-growing ones.

Conclusions:

• Active surveillance is a viable strategy for SRMs, maintaining favorable oncological outcomes.
• Clinical factors including age, tumor size, GR, and initial biopsy results guide intervention decisions.
• No disease progression or cancer-specific deaths were observed in this cohort, supporting AS safety.