Faculty Bibliography

OBJECTIVE: To assess the impact of the American Urological Association (AUA) guidelines advocating partial nephrectomy for T1 tumors guidelines on the likelihood of undergoing partial nephrectomy. MATERIALS AND METHODS: We analyzed the Nationwide Inpatient Sample (NIS), a dataset encompassing 20% of all United States inpatient hospitalizations, from 2007 through 2010. Our dependent variable was receipt of radical vs partial nephrectomy (55.50, 55.51, 55.52, and 55.54 vs 55.4) for a renal mass (International Classification of Disease, 9th Revision [ICD-9] code 189.0). The independent variable of interest was time of surgery (before or after the establishment of AUA guidelines); covariates included a diagnosis of chronic kidney disease (CKD), overall comorbidity, age, race, gender, geographic region, income, and hospital characteristics. Bivariate and multivariable adjusted logistic regression was used to determine the association between receipt of partial nephrectomy and time of guideline establishment. RESULTS: We identified 26,165 patients with renal tumors who underwent surgery. Before the guidelines, 4031 patients (27%) underwent partial nephrectomy compared to 3559 (32%) after. On multivariable analysis, undergoing surgery after the establishment of guidelines (odds ratio [OR] 1.20, 95% confidence interval [CI] 1.08-1.32, P <.01) was an independent predictor of partial nephrectomy. Other factors associated with partial nephrectomy were urban location, surgery at a teaching hospital, large hospital bed size, Northeast location, and Black race. Female gender and CKD were not associated with partial nephrectomy. CONCLUSION: Although adoption of partial nephrectomy increased after establishment of new guidelines on renal masses, partial nephrectomy remains an underutilized procedure. Future research must focus on barriers to adoption of partial nephrectomy and how to overcome them.

OBJECTIVE: To investigate gender effects on the type of nephrectomy performed for a stage I renal mass and differences that might account for disparity in treatment patterns according to gender. METHODS: Using a single-institution database, patients who underwent nephrectomy at a tertiary referral center for a localized, solitary tumor, 1 in 38% vs 50%; P = .027) and lower mean preoperative creatinine (0.09 +/- 0.3 vs 1.1 +/- 0.3; P <.001). Despite lower creatinine, women had inferior preoperative renal function with a mean estimated glomerular filtration rate of 71.4 +/- 21 vs 78.9 +/- 21 mL/min/1.73 m2 in men (P <.001). Multivariable analysis indicated that female patients were 2.5 times more likely to undergo radical nephrectomy compared with their male counterparts (P = .022). Women were less likely to have malignancy (odds ratio male gender 2.50; P = .013). CONCLUSION: Women are more likely than men to undergo radical vs partial excision of a localized renal mass, despite less comorbid burden, inferior renal function, and increased likelihood of benign disease.

PURPOSE: To assess dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) tracer pharmacokinetic parameters obtained with Generalized Kinetic Model (GKM) and extended Shutter Speed Model (SSM2) in renal tumors stratified by histologic subtypes. MATERIALS AND METHODS: In all, 24 patients with renal tumors were imaged at 1.5 T utilizing DCE-MRI with high temporal resolution (1.2 sec/temporal frame) prior to surgery. Tracer kinetic analysis was performed for the entire tumor using individualized aortic input function. GKM and SSM2 were employed to generate transfer constant (K(trans) ), plasma volume, and interstitial volume. These parameters, and DeltaK(trans) (K(trans) SSM2 - K(trans) GKM) were compared between tumors stratified by histologic subtype. RESULTS: There were 25 renal tumors: 15 clear cell, 4 papillary, 3 chromophobe, and 3 oncocytoma/oncocytic subtype. K(trans) GKM was significantly higher in chromophobe compared to other subtypes (P < 0.01). Using K(trans) GKM > 1.0 min(-1) , chromophobe were diagnosed with 100% sensitivity and 90.9% specificity. K(trans) SSM2 was higher than K(trans) GKM for all renal tumors except for all chromophobe and two clear cell subtype. Using K(trans) GKM > 1.0 min(-1) and Delta K(trans) < 0, chromophobe could be discriminated from other lesions with 100% accuracy. CONCLUSION: K(trans) obtained with GKM and SSM2 analysis can potentially discriminate chromophobe from other renal lesions with high accuracy. J. Magn. Reson. Imaging 2013;. (c) 2013 Wiley Periodicals, Inc.