Intravenous Mannitol Versus Placebo During Partial Nephrectomy in Patients with Normal Kidney Function: A Double-blind, Clinically-integrated, Randomized Trial.

BACKGROUND: Mannitol is currently used as a renal protective agent to mitigate the effects of renal ischemia during nephron-sparing surgery (NSS). This routine practice lacks rigorous methodological study. OBJECTIVE: To assess the effect on renal function outcomes after surgery of mannitol infusion prior to renal ischemia during NSS. DESIGN, SETTING, PARTICIPANTS: This prospective, randomized, placebo-controlled, double-blind trial included 199 patients with a preoperative estimated glomerular filtration rate (eGFR) >45ml/min/1.73m2 scheduled for NSS; the trial was conducted between July 2012 and July 2015. INTERVENTION: Patients undergoing NSS were randomized to receive mannitol (12.5g) or placebo intravenously within 30min prior to renal vascular clamping. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was the difference in eGFR (renal function) between the two groups at 6 mo following surgery assessed with an analysis of covariance model using preoperative eGFR, treatment group, and surgical approach as covariates. RESULTS AND LIMITATIONS: At baseline, the median age of the patients was 58 yr, and the median eGFR was 88ml/min/1.73m2. Comparing placebo with mannitol infusion, the adjusted difference of 0.2 eGFR units at 6 mo was not significant (p=0.9), with the upper bound of the 95% confidence interval (-3.1 to 3.5) excluding a clinically relevant effect of mannitol. Limitations include evaluation of a single mannitol dose and patients all had excellent preoperative renal function. CONCLUSIONS: Intraoperative 12.5g mannitol infusion during NSS has no demonstrable clinical benefit when compared with standardized fluid hydration in patients with normal preoperative renal function, and its use in this setting is not warranted. PATIENT SUMMARY: In this randomized trial, patients with normal kidney function who received mannitol during surgery to remove part of their kidney had no better kidney function 6 mo after surgery than those who did not receive mannitol. We conclude that this routine practice should be discontinued.

Second primary malignancies in renal cortical neoplasms: an updated evaluation from a single institution.

PURPOSE: To examine the incidence of secondary primary malignancies in patients with renal cortical neoplasms. METHODS: Between January 1989 and July 2010, 3647 patients underwent surgery at our institution for a renal cortical neoplasm and were followed through 2012. Occurrence of other malignancies was classified as antecedent, synchronous, or subsequent. All patients with antecedent malignancies (n = 498) and a randomly selected half of those with synchronous malignancies (n = 83) were excluded. The expected number of second primaries was calculated by multiplying Surveillance, Epidemiology, and End Results Program incidence rates of renal cortical neoplasms by person-years at risk within categories of age, sex, and year of diagnosis. The standardized incidence ratio (SIR) was calculated as observed cancers divided by expected incidence of the cancer, with approximation to the exact Poisson test used to obtain confidence intervals (CI) and p values. RESULTS: Of 3066 patients with renal cortical neoplasms, 267 had a second primary cancer; the five most common in men were prostate, colorectal, bladder, lung, and non-Hodgkin's lymphoma; the five most common in women were breast, colorectal, lung, endometrium, and thyroid. Men demonstrated higher than expected thyroid cancer rate (SIR 5.0; 95 % CI 1.83-10.88, p = 0.002), and women had higher than expected rates of stomach cancer (SIR 5.0; 95 % CI 1.61-11.67, p = 0.004) and thyroid cancer (SIR 4.62; 95 % CI 1.69-10.05, p = 0.003). CONCLUSIONS: The incidence of certain types of second malignancies may be higher in patients after diagnosis of renal cortical neoplasms compared to the general population. These observations can inform clinical follow-up in kidney cancer survivorship and future research studies.

Interobserver variability of R.E.N.A.L., PADUA, and centrality index nephrometry score systems.

PURPOSE: To assess interobserver variability of R.E.N.A.L., preoperative aspects and dimensions used for an anatomical classification system (PADUA), and centrality index (C-Index) systems among observers with varying degrees of clinical experience and each system's subscale correlation with surgical outcome metrics. METHODS: Computed tomography images of 90 patients who underwent open, laparoscopic, or robot-assisted laparoscopic partial nephrectomy were scored by one radiology fellow, two urology fellows, one radiology resident, and one secondary school student. Agreement among readers was determined calculating intraclass correlation coefficients. Associations between radiology fellow scores (reference standard as reader with greatest clinical experience), ischemia time, and percent change in postoperative estimated glomerular filtration rate (eGFR) were evaluated using Spearman's correlation. RESULTS: Agreement using C-Index method (ICC = 0.773) was higher than with PADUA (ICC = 0.677) or R.E.N.A.L (ICC = 0.660). Agreement between reference and secondary school student was lower than with other physicians, although the differences were not statistically significant. The reference's scores were significantly (p < 0.05) associated with ischemia time on all three scoring systems and with percent change in eGFR at 6 weeks using C-Index (p = 0.016). Tumor size, nearness to sinus, and location relative to polar lines (R.E.N.A.L.) and tumor size, renal sinus involvement, and collecting system involvement (PADUA) correlated with ischemia time (all p ≤ 0.001). No R.E.N.A.L. or PADUA subscales significantly correlated with percent change in postoperative eGFR. CONCLUSIONS: Clinical experience reduces interobserver variability of existing nephrometry systems though not significantly and less so when using directly measureable anatomic variables. Consistently, only measures of tumor size and distance to intrarenal structures were useful in predicting clinically relevant outcomes.

Comparison of perioperative outcomes of retroperitoneal and transperitoneal minimally invasive partial nephrectomy after adjusting for tumor complexity.

OBJECTIVE: To evaluate and compare perioperative outcomes of transperitoneal and retroperitoneal (RP) laparoscopic and robotic partial nephrectomies (LPNs) while adjusting for tumor complexity. MATERIALS AND METHODS: Retrospective review was conducted of 191 patients who underwent transperitoneal (n = 116) or RP (n = 75) LPN. To adjust for tumor complexity, individual components of the radius, exophytic or endophytic properties, nearness to the collecting system or sinus, anterior or posterior location, and location in reference to polar lines (R.E.N.A.L.) nephrometry score were used in multivariate linear and logistic regression models to compare perioperative outcomes between the 2 groups. A propensity approach was also used to adjust for multiple covariates. Investigated outcomes included estimated blood loss (EBL), ischemia and operative times, length of hospital stay, margin status, opioid use, postoperative estimated glomerular filtration rate, complications within 30 days, and readmission rates. RESULTS: Tumors resected by RPLPN were more likely to have lower complexity score by nephrometry (P = .04). Four of the 5 components of the R.E.N.A.L. nephrometry score were significantly different between the groups. After adjustment for these factors, a lower EBL was noted in the RP group (ß, -97; 95% confidence interval, -156 to -39; P = .001). Risk of readmission for the RP group was significantly lower (odds ratio, 0.15; P = .024) using propensity analysis. CONCLUSION: Using adjustment for tumor complexity, RPLPN was associated with lower EBL and readmission rates supporting the potential clinical advantage for this approach when feasible.