Introduction: Reported outcomes for active surveillance (AS) in patients with small renal masses (SRM) are heavily biased towards older and unhealthier patients. The safety, tolerability and rates of delayed intervention (DI) for AS in younger and healthier SRM patients remains largely unexplored. Here we report outcomes at a single center for SRM patients with estimated life expectancy (LE) >20 years who were managed with AS +/- DI. Methods: From January 2013-March 2019, all patients with non-hereditary SRM presenting to a single urologic oncologist at a National Comprehensive Cancer Network institute were recommended AS if predefined progression criteria for intervention (PCI) were absent. PCI was defined prospectively as any SRM-related symptoms, unfavorable biopsy histology, cT3a stage, or either of the following without benign neoplastic biopsy histology: longest tumor diameter (LTD) >4 cm; growth rate >5 mm/year for LTD =3 cm or >3 mm/year for LTD >3 cm. DI was considered during AS only upon PCI development. Patients with LE >20 years were retrospectively identified. LE was estimated using social security LE estimations adjusted by age, gender, and Charlson Comorbidity Index. The 3- and 5-year rates of PCI-freedom and DI-freedom were determined. Results: Among 90 consecutive SRM patients with LE >20 years (median age 57, IQR 47-61), 89 (99%) patients (101 SRMs) did not meet PCI at presentation and underwent AS. With median follow-up of 44 months, 31/89 (35%) AS patients developed PCI, of whom 21/31 (68%) underwent DI (all surgery). One (1%) AS patient crossed over to DI without PCI development. 3- and 5-year PCI-free rates were 68% and 56%, respectively, and 3- and 5-year DI-free rates were 75% and 67%, respectively. No patient developed metastasis. Conclusions: AS using predefined PCI in otherwise unselected SRM patients is well tolerated and allows most SRM patients with >20 years LE to avoid treatment over 5 years. Long-term DI rates and oncologic safety in younger/healthier patients require further study. SOURCE OF Funding: None
