BJUI BJU INTERNATIONAL © 2012 THE AUTHORS 1270 BJU INTERNATIONAL © 2 0 1 2 B J U I N T E R N A T I O N A L | 11 0 , 1 2 7 0 – 1 2 7 5 | doi:10.1111/j.1464-410X.2012.11130.x What’s known on the subject? and What does the study add? Active surveillance of small renal masses has traditionally been reserved for elderly patients deemed unfit for surgery or ablation. There is increasing evidence showing the safety of active surveillance in the management of small renal masses. In this retrospective study we compared outcomes for patients with small renal masses managed with active surveillance, radical nephrectomy and partial nephrectomy. We showed that active surveillance was safe and appeared as effective as immediate surgery in the management of small renal tumours. OBJECTIVE • To compare the oncological outcomes of active surveillance (AS), radical nephrectomy (RN) and partial nephrectomy (PN) in the management of T1a small renal masses (SRMs). PATIENTS AND METHODS • At present AS is used in the treatment of SRMs in elderly patients with multiple co-morbidities or in those who decline surgery. • We identified all patients with T1a SRMs managed with RN, PN or AS. • Retrospective data were collected from patient case records with survival data and cause of death cross-referenced with the Oxford Cancer Intelligence Unit. RESULTS • A total of 202 patients with 234 T1a SRMs (solid or Bosniak IV) were identified; 71 patients were managed with AS, 41 with an RN and 90 by PN. • Over a median follow-up of 34 months the mean growth rate on AS was 0.21 cm/ year with 53% of SRMs managed with AS showing negative or zero growth. • No statistically significant difference was observed in overall (OS) and cancer-specific (CSS) survival for AS, RN and PN (AS-CSS 98.6%, AS-OS 83%; RN-CSS 92.6%, RN-OS 80.4%; PN-CSS 96.6%, PN-OS 90.0%). CONCLUSIONS • Active surveillance of SRMs offers oncological efficacy equivalent to surgery in the short/intermediate term. • The results of this study support a multicentre prospective randomized controlled trial designed to compare the oncological efficacy of AS and surgery. KEYWORDS active surveillance, renal carcinoma, small mass Study Type – Therapy (case series) Level of Evidence 4 Active surveillance of small renal masses offers short-term oncological efficacy equivalent to radical and partial nephrectomy Nilay Patel, David Cranston, M. Zeeshan Akhtar , Caroline George, Andrew Jones, Aaron Leiblich, Andrew Protheroe and Mark Sullivan Department of Urology, Churchill Hospital, Headington, Oxford, UK INTRODUCTION The incidence of renal cancer has been increasing in Europe and the USA since the 1980s [1–3]. An increase in the use of cross-sectional imaging over this period has resulted in a downward stage migration at presentation with an increasing proportion of patients presenting with small renal masses (SRM) < 4 cm in size [4–6]. Increased detection rates of early stage disease have resulted in increased rates of surgery for SRMs, the benefits of which remain unclear. There are conflicting reports on improvements in mortality rates for renal cancer over the past few years [5,7], suggesting that increased detection and earlier treatment may not necessarily be improving the survival of patients with T1a renal cancer. Numerous treatment options have been available to patients presenting with SRMs inclding radical nephrectomy (RN), partial nephrectomy (PN), ablative therapies (cryotherapy, radiofrequency ablation, high-intensity focused ultrasound) and active surveillance (AS). The current guidelines for the treatment of T1 renal cancer from the AUA and the European Association of Urology have suggested performing a PN whenever possible in the surgically fit patient [8,9]. A recent study from the USA has shown the increased use of nephron-sparing techniques over the past decade; however, in 2007 only 32.2% of T1 renal masses were managed with a PN, 57.7% with an RN, 6.8% with ablative therapy and 3.3% with AS [10]. A significant number of SRMs are diagnosed as incidental tumours often in elderly Accepted for publication 20 December 2011