title: Percutaneous cryoablation of stage T1b renal cell carcinoma: technique considerations, safety, and local tumor control.
abstract: OBJECTIVE
  To describe the technical methods, safety, and local tumor control rate associated with percutaneous cryoablation of stage T1b renal cell carcinoma (RCC).
  
  
  METHODS
  A retrospective review of a percutaneous renal ablation registry was used to identify 46 patients with a total of 46 biopsy-proven RCC lesions measuring 4.1-7.0 cm treated with cryoablation between 2003 and 2011. The main outcome parameters investigated were adjunctive maneuvers, complications, and local tumor progression, and cancer-specific survival rates. Complication rates were categorized and recorded using the Clavien-Dindo classification system. Progression-free and cancer-specific survival rates were estimated using the Kaplan-Meier method.
  
  
  RESULTS
  The mean treated RCC size was 4.8 cm (range, 4.1-6.4 cm). Prophylactic tumor embolization was performed in 7 patients (15%), ipsilateral ureteral stents were placed in 7 patients (15%), and hydrodisplacement of bowel was performed in the treatment of 16 tumors (35%). A single technical failure (2.2%) was observed at the time of ablation. Thirty-six tumors (78%) had follow-up imaging at 3 months or later following ablation, including a single recurrence at 9 months after ablation. The mean duration of follow-up for the 35 RCC tumors that did not recur was 2.0 years (range, 0.3-6.1 y). Estimated local progression-free survival rate at 3 years was 96.4%. Of the 46 cryoablation procedures, there were 7 complications (15.2%) of grade II or worse.
  
  
  CONCLUSIONS
  The results suggest that cryoablation represents a valid treatment alternative for select patients with clinical stage T1b RCC. Complications are frequent enough that multidisciplinary patient management should be considered.
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.. Electronic address: atwell.thomas@mayo.edu.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Atwell
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Jay J
authors.initials: JJ
authors.lastname: Vlaminck
authors.affiliation: Urology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boorjian
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Anil N
authors.initials: AN
authors.lastname: Kurup
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Callstrom
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Weisbrod
authors.affiliation: Biostatistics, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Lohse
authors.affiliation: Anesthesiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: William R
authors.initials: WR
authors.lastname: Hartman
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Stockland
authors.affiliation: Urology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
authors.affiliation: Departments of Radiology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Grant D
authors.initials: GD
authors.lastname: Schmit
authors.affiliation: Urology, Mayo Clinic, Mayo Building, E2, 200 First St. SW, Rochester, MN 55905.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Thompson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D003452:Cryosurgery / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D018450:Disease Progression; D018572:Disease-Free Survival; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011183:Postoperative Complications / Q000209:etiology; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden