Related Experiment Video
Updated: Apr 30, 2026
In Vivo, Percutaneous, Needle Based, Optical Coherence Tomography of Renal Masses
Published on: March 30, 2015
Active surveillance for renal masses up to 2 cm: long-term oncological outcomes from a prospective
Chiara Re1,2, Alessandro Bertini3,4, Pietro Scilipoti1,2
1Division of Experimental Oncology/Unit of Urology, Urological Research Institute (URI), IRCCS San Raffaele Scientific Institute, Via Olgettina, 60, 20132, Milan, Italy.
Purpose:
The widespread use of cross-sectional imaging has increased the incidental detection of small renal masses (SRMs). In this context, overtreatment represents a major concern, particularly for lesions < 2 cm. Most evidence derives from retrospective registries, whereas prospective data remain limited.
Methods:
This multi-center, prospective, non-randomized clinical trial was conducted in five European centers between January 2015 and July 2021. Seventy-six patients aged > 50 years with asymptomatic, unilateral SRM < 2 cm were enrolled and followed under a structured prospective active surveillance (AS) protocol with periodic axial imaging. Active treatment was recommended according to predefined progression criteria or patient preference. The primary endpoint was event-free survival (EFS); secondary endpoints included treatment-free survival (TFS), overall survival (OS), and cancer-specific mortality (CSM).
Results:
69 patients were included in the analyses. After a median follow-up of 88 months, 8-year EFS and TFS were 66% and 83%, respectively. 17% of patients required active treatment, mainly due to tumor growth. The 8-year OS and CSM were 88% and 9.6%. One patient died of metastatic RCC. Shorter tumor doubling time (DT) (< 12 years) and high RENAL score were significantly associated with higher risks of event and treatment. Endophytic tumors, and higher PADUA score also predicted adverse outcomes.
Conclusion:
Long-term follow-up confirms AS as the standard initial option for selected patients with SRMs ≤ 2 cm, with a low rate of progression and optimal survival rates. Tumor DT and mass location should be considered in clinical decision-making to identify patients who will deserve a deferred treatment in case of progression.
Insights
Active surveillance (AS) is a safe initial approach for small renal masses (SRMs) under 2 cm, showing good survival rates and low progression. Tumor doubling time and mass location help guide deferred treatment decisions for SRMs.
Area of Science:
- Urology
- Oncology
- Radiology
Background:
- Cross-sectional imaging frequently detects small renal masses (SRMs), leading to concerns about overtreatment of lesions < 2 cm.
- Prospective data on managing SRMs are limited, with most evidence from retrospective studies.
Purpose of the Study:
- To evaluate the efficacy and safety of prospective active surveillance (AS) for asymptomatic SRMs < 2 cm.
- To determine event-free survival (EFS), treatment-free survival (TFS), overall survival (OS), and cancer-specific mortality (CSM) in patients managed with AS.
Main Methods:
- A multi-center, prospective, non-randomized clinical trial involving 76 patients aged > 50 years with SRMs < 2 cm.
- Patients underwent structured AS with periodic imaging; treatment was initiated based on progression criteria or patient preference.
Main Results:
- After a median follow-up of 88 months, 8-year EFS was 66% and TFS was 83%.
- 17% of patients required active treatment, primarily due to tumor growth. 8-year OS was 88% and CSM was 9.6%.
- Shorter tumor doubling time (< 12 years), high RENAL and PADUA scores, and endophytic tumors predicted adverse outcomes.
Conclusions:
- Long-term follow-up supports AS as the standard initial management for selected SRMs ≤ 2 cm, demonstrating low progression rates and favorable survival.
- Tumor doubling time and mass location are crucial factors for clinical decision-making, identifying patients who may benefit from deferred treatment.
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