CURRENT STATUS OF SIMPLE ENUCLEATION IN THE SCENARIO OF NEPHRON-SPARING SURGERY: A SYSTEMATIC REVIEW OF THE LITERATURE

Introduction/Aim: Nephron-sparing surgery (NSS) is the gold standard treatment for localized renal tumors. At present, NSS can be performed either as standard partial nephrectomy (PN) defined as the excision of the tumor and of an additional margin of healthy peritumor renal parenchyma or as simple enucleation (SE)/enucleative partial nephrectomy. The aim of this review is to critically analyze the current status of SE in NSS. Materials and Methods: A systematic review of the literature was performed using the Medline, Embase, Web of Science and Cochrane Library databases up to September 2014. Papers were rated through the International Consultation on Urological Diseases (ICUD) Levels of Evidence (LE) scale. The final GR was given following the ICUD rules for developing and grading guideline recommendations. Results: Thirty-four studies have been published in literature on SE (Table I). Three were reviews of case series, while 31 original papers. Of these, 3 (10%) were good quality prospective cohort studies (LE 2), 20 (64%) good quality case series (LE 3) and 8 (26%) expert opinions (LE 4). The great majority of the evidence highlighted the positive value of SE; the overall GR is B. A synthesis of the evidence is presented. SE can be performed with open, laparoscopic and robotic approaches for T1a-T1b tumors (LE3; Grade C), both as elective treatment and for relative/absolute indications to NSS (LE3; Grade B). High Fuhrman grade might be a contraindication, even if no final recommendations can be stated. A possible advantage of SE was reported for tumors with unfavorable nephrometric scores (LE4; Grade C). Warm ischemia time (WIT) and perioperative complications are similar between SE and standard PN (LE3; Grade C), as well as local recurrence-free survival and cancer-specific survival (CSS) for T1a-T1b tumors (LE2-3; Grade B). SE is at least non-inferior to standard PN regarding the risk of positive SMs (LE3; Grade C). Most studies found no difference in progression-free survival between patients with and without neoplastic penetration of the pseudocapsule at long-term follow-up after SE. No comparative data on mid- and long-term functional outcomes have been reported to date. Discussion and Conclusion: The evidence in literature highlights the oncologic safety of SE. Some studies have shown a lower incidence of positive SMs for SE compared to standard PN. However, there is a substantial lack of standardized reporting in literature. Some studies do not even use the term “enucleation”; therefore, they could not be included in the analysis, losing a great body of evidence. Prospective studies are warranted to test the efficacy of SE for tumors with adverse nephrometric scores and to compare the results with standard PN. To date, the GR for SE is rather high. Nonetheless, the LE is still not optimal. Defining surgical standards in NSS is warranted to achieve a more appropriate analysis of literature and a clearer comparison of different techniques.