Introduction: Metastatic risk for small renal mass (SRM) patients on active surveillance (AS) is low and often outweighed by treatment morbidity. Rates of treatment conversion in unselected SRM patients based on specific radiographic/histologic progression criteria are unknown. We report our updated experience with “universal AS” management, which uses defined clinical progression criteria for triggering treatment, and recommends AS to all SRM patients who lack these criteria
Methods: All non-end stage renal disease patients with SRM tumors presenting from January 2013 to September 2017 to a single urologic oncologist at a National Comprehensive Cancer Network institute were recommended AS if specific radiographic/histologic progression criteria for triggering treatment were absent at presentation. Progression criteria included any of the following in the absence of benign tumor biopsy histology: longest tumor diameter (LTD) >4 cm, growth rate >5 mm/year, LTD >3 cm + growth rate =3 mm/year, high risk biopsy histology, >cT3a stage, or symptoms. Biopsy was performed for LTD >2 cm. Outcome measures included progression-free survival (PFS) and metastasis-free survival (MFS).
Results: Of 127 SRM patients (143 tumors) with no prior RCC history and >3 months follow up, 4 met progression criteria at presentation and were recommended treatment. All remaining 123 SRM patients (median LTD 2.2, range 0.9-3.9 cm) were managed with AS. Over a median follow up was 31 (range 6-68) months, 36 (29%) AS patients met >/=1 progression criterion, leading to treatment conversion in most cases (28 resection, 1 ablation). 3-year PFS and MFS rates were 70% and 100%, respectively; lower PFS rates were associated with initial LTD (84% for <2 cm, 75% for 2.1-3 cm, 49% for >3cm) and clear cell RCC biopsy histology (43%) (Figure). Resected tumors were enriched for adverse pathology (64% high grade and/or pT3a) and malignant histology (100% RCC). Only 1 (1%) non-progressing patient converted to treatment (anxiety).
Conclusions: Universal AS using specific clinical progression criteria allows treatment avoidance for many SRM patients (particularly if LTD <3 cm), and improves identification of more aggressive tumors for treatment selection. Longer follow up is needed to assess the durability and oncologic safety of universal AS for SRM patients. Source of