SIMPLE ENUCLEATION VERSUS STANDARD PARTIAL NEPHRECTOMY FOR CLINICAL T1 RENAL TUMORS: A PROSPEC- TIVE MULTICENTER COMPARATIVE STUDY (RECORD PRO- JECT)

Aim of the study Aim of this study is to evaluate surgical and postoperative outcomes of SE and standard PN in a prospective multicenter dataset. Materials and methods The RECORd Project is a 4-year prospective observational multi- center study promoted by SIU. The study includes all patients who underwent open or laparoscopic nephron-sparing surgical treatment for kidney cancers between January 2009 and January 2011 at 19 Italian centers. Approval of the study protocol by the local ethical committee was obtained at each centre. Conservative sur- gery was performed in the form of standard partial nephrectomy (PN) and simple tumor enucleation (SE) according to center’s and surgeon’s preference. Standard PN has been defined as the excision of the tumor and of an additional margin of healthy peritumoral renal parenchyma. SE, as the tumor excision without a visible rim of parenchyma tissue around the pseudocapsule. The standard PN group and the SE group were compared regarding clinical, surgical, and pathologic outcome variables. Multivariable logistic regression models were applied to analyze predictors of warm ischemia time (WIT) >20 minutes and positive surgical margin status (PSM). Results Overall, 535 patients were the subject of the final analysis. 226x had SE and 309 standard PN. SE was associated with a significantly longer WIT (18.3 min vs. 16.2 min, p=0.0022) and a significantly lower intraoperative blood loss (180 cc vs. 248 cc; p=0.0084) and shorter operative time (122 min vs. 151 min; p 20 minutes). The incidence of PSM was significantly lower in patients treated with SE compared with standard PN (1.3% vs. 6.7%; p=0.01). At multivariate analysis the only factor significantly correlated with the risk of PSM was the surgical technique, with a 5-fold increased risk of PSM for standard PN compared to SE. Overall, 119 postoperative complications were recorded in 114 patients (21.3%). Surgical and medical complications were 89 (16.6%) and 30 (5.6%). Surgical complications according to the modified Clavien classification were: grade 1 (21.4%), grade 2 (48.3%), grade 3 (30.3%). No grade 4 and 5 surgical complications occurred. No significant differences between surgical techniques were observed in terms of incidence of surgical complications, Clavien II and Clavien III surgical complications. Discussion This study represents the first prospective comparative multicenter study between SE and standard PN. Conclusions In our series of T1 RCC the incidence of positive surgical margins was significantly lower in patients treated with SE vs. standard PN. No difference was found in WIT >20 minutes and surgical complication rate between the two techniques.