Nephron sparing surgery (NSS) and minimally invasive modality of thermal ablation have attracted great attention as an alternative surgical treatment to radical nephrectomy (RN) for renal tumours <4cm. High quality evidence comparing disease specific survival (DSS) is lacking. This issue was addressed in this study. The authors have retrospectively examined data obtained from a USA population-based cohort of nearly 9000 patients treated for renal tumours <4cm with either NSS (7704 patients) or ablation (1114 patients) between 1998 and 2007. Multiple variables were assessed including age, tumour characteristics (size and tumour, node, metastasis (TNM) stage), and marital and economical status along with other social variables. The primary outcome was DSS. The median follow-up in each group was less than five years in each group. Over the short follow-up period, the overall DSS was high for both treatments; however, the authors detected a small but significant difference in the risk of death from renal cancer in favour of the NSS group. After adjusting for several variables, Whitson et al. concluded an ‘at least two fold’ increase in the risk of death related to kidney cancer among patients who received ablative therapy. The present study produced the ‘first well powered’ study to compare effectiveness of NSS to ablation. The results formed level two evidence in support of NSS especially for patients with long life expectancy. The authors have acknowledged several limitations to this study including the relatively short follow-up and the retrospective, non-randomised, and non-controlled nature.