title: Percutaneous microwave ablation of T1a and T1b renal cell carcinoma: short-term efficacy and complications with emphasis on tumor complexity and single session treatment.
abstract: To update the oncologic outcomes and safety for microwave (MW) ablation of T1a (≤4.0 cm) and T1b (4.1-7.0 cm) renal cell carcinoma (RCC) with emphasis on tumor complexity and single session treatment.
  
  
  
  Retrospective review of 29 consecutive patients (30 tumors) with localized (NOMO) RCC (23 T1a; 7 T1b) treated with percutaneous MW ablation between 3/2013 and 6/2014. Primary outcomes investigated were technical success, local tumor progression (LTP), and complications. Technical success was assessed with contrast-enhanced computed tomography (CECT) immediately after MW ablation. Presence of LTP was assessed with CECT or contrast-enhanced magnetic resonance at 6-month target intervals for the first two years and annually thereafter. Complications were categorized using the Clavien-Dindo classification system.
  
  
  
  Median tumor diameter was 2.8 cm [IQR 2.1-3.3] for T1a and 4.7 cm [IQR 4.1-5.7] for T1b tumors. Median RENAL nephrometry score was 7 [IQR 4-8] for T1a tumors and 9 [IQR 6.25-9.75] for T1b tumors. Technical success was achieved for 22 T1a (96%) and 7 T1b (100%) tumors. There were no LTP during a median imaging follow-up of 12.0 months [IQR 6-18] for the 23 patients (24 tumors) with greater than 6 months of follow-up. There were three Clavien-Dindo grade I-II complication (10%) and no Clavien-Dindo grade III-V complications (0%). All but two patients (93%) are alive without metastatic disease; two patients died after 12-month follow-up of causes unrelated to the MW ablation.
  
  
  
  Percutaneous MW ablation appears to be a safe and effective treatment option for low, moderate, and highly complex T1a and T1b RCC in early follow-up.
authors.affiliation: Department of Radiology, University of Wisconsin, 600 Highland Avenue, E3/376, Madison, WI, 53792, USA. swells@uwhealth.org.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Wells
authors.affiliation: Department of Urology, University of Virginia, 1215 Lee Street, Charlottesville, VA, 22903, USA.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Wheeler
authors.affiliation: Department of Radiology, University of Virginia, 1215 Lee Street, Charlottesville, VA, 22903, USA.
authors.forename: Ayman
authors.initials: A
authors.lastname: Mithqal
authors.affiliation: Department of Urology, University of Virginia, 1215 Lee Street, Charlottesville, VA, 22903, USA.
authors.forename: Mehul S
authors.initials: MS
authors.lastname: Patel
authors.affiliation: Department of Biomedical Engineering, Wisconsin Institutes of Medical Research, 111 Highland Avenue, Madison, WI, 53705, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
authors.affiliation: Department of Urology, University of Virginia, 1215 Lee Street, Charlottesville, VA, 22903, USA.
authors.forename: Noah S
authors.initials: NS
authors.lastname: Schenkman
mesh_terms: D000368:Aged; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media
keywords: Microwave ablation; RCC; Renal cell carcinoma; Tumor ablation