title: Percutaneous radiofrequency ablation therapy for hepatocellular carcinoma: a proposed new grading system for the ablative margin and prediction of local tumor progression and its validation.
abstract: BACKGROUND
  In the present study we classified the radicality of percutaneous radiofrequency thermal ablation (RFA) therapy according to the extent of the ablated margin. We measured the local recurrence rate for each radicality grade to evaluate the significance of the grading system in assessing the therapeutic effectiveness of RFA and predicting local tumor progression.
  
  
  METHODS
  This retrospective study involved 269 patients with solitary hypervascular hepatocellular carcinoma who had undergone RFA. The mean ± SD observation period after RFA, number of treatment sessions, and tumor diameter were 25.7 ± 19.9 months, 1.2 ± 0.5, and 2.1 ± 0.7 cm, respectively. Patients were evaluated using dynamic computed tomography. We classified the radicality of RFA treatment into four grades (R grades: A, B, C, and D) according to the extent of the ablated tumor margin, calculated the post-RFA cumulative local recurrence rate for each R grade, and analyzed the factors (patient characteristics, biochemical data, contiguous vessels, and tumor marker) contributing to local recurrence.
  
  
  RESULTS
  The cumulative local recurrence rates at 3 years were 6.7, 17.6, 55.8, and 82.2% for Grades A, B, C, and D, respectively. Using univariate analysis, R grade, tumor size (> 2 cm), and des-γ-carboxy prothrombin (DCP) (> 200 mA U/mL) were shown to be significant factors contributing to local recurrence. However, using multivariate analysis, only the R grade was found to be a significant independent factor.
  
  
  CONCLUSIONS
  The proposed R grading method is a valid and useful method for assessing treatment efficacy, and for predicting local tumor progression after RFA.
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka Red Cross Hospital, 5-30 Fudegasaki-cho, Tennoji-ku, Osaka 543-0027, Japan. h-nishikawa@osaka-med.jrc.or.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nishikawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Inuzuka
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Takeda
authors.forename: Jun
authors.initials: J
authors.lastname: Nakajima
authors.forename: Azusa
authors.initials: A
authors.lastname: Sakamoto
authors.forename: Sinichiro
authors.initials: S
authors.lastname: Henmi
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Matsuda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Eso
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Sumio
authors.initials: S
authors.lastname: Saito
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kita
authors.forename: Toru
authors.initials: T
authors.lastname: Kimura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Osaki
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D011498:Protein Precursors / Q000378:metabolism; D011516:Prothrombin / Q000378:metabolism; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; D011498:Protein Precursors; C008208:acarboxyprothrombin; D011516:Prothrombin