title: Tumor Growth Kinetics and Oncologic Outcomes of Patients Undergoing Active Surveillance for Residual Renal Tumor following Percutaneous Thermal Ablation.
abstract: OBJECTIVE
  To evaluate growth kinetics and oncologic outcomes of patients with renal tumors undergoing active surveillance (AS) for residual viable tumor following percutaneous ablation.
  
  
  METHODS
  Following percutaneous thermal ablation, residual tumor was detected in 21/133 (16%) patients on initial follow-up imaging, and AS was undertaken in 17/21 (81%) patients. Initial tumor volumes and volumes after ablation were assessed from cross-sectional imaging to calculate volumetric growth rate (VGR) and volume doubling time (VDT) of residual tumor. The rate of metastasis, overall survival, and renal cell carcinoma (RCC)-specific survival were compared between patients in the AS group and in the routine follow up group of patients who did not have residual tumor.
  
  
  RESULTS
  Median tumor volume prior to ablation, after first ablation, and at final follow-up were 25 cm(3), 6 cm(3), and 6 cm(3), respectively, in patients with residual tumor. Stable, mild, and moderate VGR occurred in 8/17 (47%), 4/17 (24%), and 5/17 (29%) cases, respectively. The 4 cases with fastest VDT underwent delayed intervention with ablation (n = 1) and nephrectomy (n = 3) without subsequent residual, recurrence, or metastasis. There was no significant difference in the rates of RCC metastasis, overall survival, or RCC-specific survival between AS and routine follow-up groups. Metastatic RCC and subsequent death occurred in 1 patient in the AS group, after the patient had refused offers for retreatment for local progression over 60.7 months of follow-up.
  
  
  CONCLUSIONS
  In cases when patients are not amenable to further intervention, AS of residual tumor may be an acceptable alternative and allows for successful delayed intervention when needed.
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: James X
authors.initials: JX
authors.lastname: Chen
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Daniel
authors.initials: D
authors.lastname: Maass
authors.affiliation: Division of Urology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Guzzo
authors.affiliation: Division of Urology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: S
authors.initials: S
authors.lastname: Bruce Malkowicz
authors.affiliation: Division of Urology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Wein
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Soulen
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Timothy W I
authors.initials: TWI
authors.lastname: Clark
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Nadolski
authors.affiliation: Division of Interventional Radiology, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104. Electronic address: stav@uphs.upenn.edu.
authors.forename: S
authors.initials: S
authors.lastname: William Stavropoulos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000401:mortality; D049109:Cell Proliferation; D002470:Cell Survival; D003452:Cryosurgery / Q000009:adverse effects / Q000401:mortality; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018365:Neoplasm, Residual; D009392:Nephrectomy; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden; D057832:Watchful Waiting