Nephron-sparing surgery.

Renal cell carcinoma (RCC) is a common malignancy with an increasing incidence.1 2 The classic triad of abdominal mass, hematuria, and flank pain accompanied by the various associated paraneoplastic syndromes (or the “internist's tumor”) are rare presentations of contemporary kidney cancer. With the current use and practice of modern abdominal imaging, more than half of all renal tumors are incidentally discovered at a low stage during evaluation for other conditions. The renal mass has become increasingly amenable to treatment given this stage migration. Therefore, in the modern era, it might be more appropriate to refer to RCC as the “radiologist's tumor” rather than the internists. The International Union Against Cancer staging system for RCC defines a stage 1 renal mass as an organ-confined tumor up to 4.0 cm in diameter (T1a), and between 4.1 and 7.0 cm in diameter (T1b). The American Urological Association (AUA) published guidelines for the management of stage 1 renal mass in 2009 and had validity confirmed in 2010.3 The AUA's thorough review is a must read for any practitioner treating renal masses. The National Comprehensive Cancer Network (NCCN) also provides guidance on the management of stage 1 renal masses.4 In this review, a small renal mass (SRM) is considered a T1a renal mass. The majority of SRMs will be RCCs; however many, approximately 20% will have benign histology.5 Even many of those classified as kidney cancer may have an indolent clinical course with limited growth and low risk of metastasis.6 Malignant potential is an important consideration when contemplating the permanent removal of a renal unit. Stage 1 renal masses are often successfully treated with nephron-sparing surgery (NSS) and this is the preferred approach to the resectable SRM. For this article, NSS will include only surgical partial nephrectomy, but ablative therapies such as cryoablation and radiofrequency ablation are also successfully used to preserve renal tissue on an ipsilateral renal unit. NSS was proven feasible decades ago for patients with imperative indications to preserve maximum kidney function, for instance solitary kidney, bilateral renal tumors, or moderate/severe chronic kidney disease (CKD).7 This allowed for expansion of NSS into general use for the stage 1 renal mass. Pathologic studies have shown underlying renal disease is commonly present in presumably “normal” kidneys, and outcomes studies clearly demonstrate new CKD development after nephrectomy.8 CKD has been linked to cardiovascular disease, hospitalization, and death in a population-based study of more than 1 million patients.9 This study challenges the notion that the loss of a renal unit does not significantly impact long-term health outcomes. Unfortunately NSS is widely underutilized. An evaluation of a nationwide hospital database determined only 9% of patients with surgically treatable renal tumors were treated with NSS.7 There are varied reasons for the underuse of NSS; the complexity of the surgical endeavor, an under appreciation for the impact of radical nephrectomy (RN) on health outcomes, and peculiar financial incentives seem to contribute to underutilization. NSS does have more short-term complications compared with total nephrectomy, and the oncologic efficacy had not been proven in a randomized trial. Starting in 1992, the European Organization for Research and Treatment of Cancer (EORTC) attempted to perform a randomized trial of elective NSS and RN for renal masses 5 cm or smaller10; however, the study closed early due to poor accrual and has raised many statistical questions. The published data, however, should be carefully considered, and one safe conclusion from the trial is that both RN and NSS provide excellent oncologic control. There were more local recurrences (albeit few in total) in the NSS group.