title: Renal mass biopsy and thermal ablation: should biopsy be performed before or during the ablation procedure?
abstract: To determine if renal mass biopsy should be performed before or during the ablation procedure with emphasis on complications and rate of ablation for renal cell carcinomas (RCC), benign tumors, and small renal masses without a histologic diagnosis.
  
  
  
  This HIPAA-compliant, single-center retrospective study was performed under a waiver of informed consent from the institutional review board. Two hundred eighty-four consecutive patients with a small renal mass (≤4.0 cm) treated with percutaneous thermal ablation between January 2001 and January 2015 were included. Two cohorts were identified based upon the timing of renal mass biopsy: separate session two weeks prior to ablation and same session obtained immediately preceding ablation. Clinical and pathologic data were collected including risk factors for non-diagnostic biopsy. Two-sided t test, χ2test or Fischer's exact tests were used to evaluate differences between cohorts. Univariate and multivariate logistic regression models were constructed.
  
  
  
  A histologic diagnostic was achieved more frequently in the separate session cohort [210/213 (98.6%) vs. 60/71 (84.3%), p < 0.0001]. The rate of ablation of RCC was higher in the separate session group [201/213 (94.4%) vs. 46/61 (64.7%), p = 0.001]. The rate of ablation for benign tumors [14/71 (19.7%) vs. 6/213 (2.8%), p < 0.0001] and small renal masses without a histologic diagnosis [3/213 (1.4%) vs. 11/71 (15.5%), p < 0.0001] was higher in the same session cohort. There were no high-grade complications in either cohort.
  
  
  
  Performing renal mass biopsy prior to the day of ablation is safe, increases the rate of histologic diagnosis, and reduces the rate of ablation for benign tumors and small renal masses without a histologic diagnosis.
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA. swells@uwhealth.org.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Wells
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.
authors.forename: Vincenzo K
authors.initials: VK
authors.lastname: Wong
authors.affiliation: Health Sciences Learning Center, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: Tyler A
authors.initials: TA
authors.lastname: Wittmann
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Lubner
authors.affiliation: Department of Urology, University of Wisconsin Medical Foundation Centennial Building, Third Floor, 1685 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Best
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Ziemlewicz
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.|Department of Urology, University of Wisconsin Medical Foundation Centennial Building, Third Floor, 1685 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.|Department of Urology, University of Wisconsin Medical Foundation Centennial Building, Third Floor, 1685 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
authors.affiliation: Department of Radiology, E3/366 Clinical Science Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.|Department of Urology, University of Wisconsin Medical Foundation Centennial Building, Third Floor, 1685 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: E Jason
authors.initials: EJ
authors.lastname: Abel
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D061705:Image-Guided Biopsy; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015641:Radiography, Interventional; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
chemical_list: D003287:Contrast Media
keywords: Oncocytoma; RCC; Renal cell carcinoma; Renal mass biopsy; Tumor ablation