This is a retrospective study to evaluate kidney function and overall survival (OS) in patients who underwent partial nephrectomy (PN) and radical nephrectomy (RN) for RCCs <4cm. They looked at 2110 patients who underwent RN/PN for T1a renal cell carcinomas (RCCs) with normal contralateral kidneys and normal serum creatinine over a 23-year period. Primary endpoints were incidence of chronic kidney disease (CKD), OS, new glomerular filtration rate (GFR) <60ml/min/1.73m². During analysis, differences were noted between the two groups of patients in that the patients who underwent RN had comparatively higher age, lower ASA, larger tumours, higher percentage dropped into CKD range eGFR postoperatively, quicker than PN arm, earlier median time to death, lesser probability of survival, and higher death per year. Five-year freedom from eGFR dropping to <60 was 24% and 76% for RN and PN, respectively. Median time to death for the RN group was 14 years and median time to death for the PN group was 20 years. Patients who underwent RN had a higher rate of death per year compared with those who underwent PN. They also compared the MDRD and CKD-EPI equation and the latter seemed better for GFR >60. Using the CKD-EPI equation for the same cohort, it was found that 21% of those with normal baseline serum creatinine levels had pre-existing stage III CKD. They conclude that RN increases morbidity and also induces worse OS than PN. OS was only significantly associated with a decline in eGFR for patients with pre-existing CKD. These results are seemingly counterintuitive as RN compared with PN is associated with development of CKD and hypertension was protective. Multivariable analysis demonstrated this finding with hypertension in our study as well. The mechanism by which hypertension is protective in this setting is unclear and worth further study. Authors recognise limitations – non randomised, retrospective studies at a single centre apart from bias. The study supports the EORTC 30904 study and advices to try PN in as many situations as possible.