Baseline estimated Gomerular Filtration rate influences need for intervention in small renal masses.

Background: Management of small renal masses (SRMs), mostly detected incidentally is a challenge. The prediction of growth trajectory as a surrogate marker for malignancy and aggressiveness remains poor. The study was aimed at finding out growth prediction and need of interventions in SRMs in patients opting for active surveillance in a stable population. 
Patients and Methods: 151 consecutive patients diagnosed with SRMs between January 2012 and December 2014 opting for active surveillance after discussions in a multidisciplinary settings were recruited into this study. Patients were followed up using imaging at intervals of 6-12 months and progression was recorded in a database. A number of factors were evaluated as predictors of growth in size including age, sex, baseline size, co-morbidities, laterality, socioeconomic status and base line eGFR. Univariate and multivariate analyses were carried out using cox-proportional hazard model to assess the best predictor/s of growth. 
Results: Mean age of population was 69.9 (±13.3) with more than half were males (87 (57.6%). Forty five (29.8%) cases showed progression with 38 (25.2%) showing increase in size of tumours size and 7 cases (4.6%) metastasized. Our multivariate analyses have shown that lower eGFR alone have significant association with increase in tumour size (chi2=5.903, p=<.05) with an odd ratio of 2.9 more likely of getting SRM if patient eGFR is less than 60. None of the other factors such as baseline size, age, sex, bilateralism and socioeconomic status showed any significance. Commonest intervention was surgical excision followed by minimally invasive ablation-most commonly RFA. 
Conclusions: Poor renal function is associated with significant increase in progression of size in patients with small renal masses and need for interventions.