title: Interobserver variability in gross tumor volume delineation for hepatocellular carcinoma : Results of Korean Radiation Oncology Group 1207 study.
abstract: OBJECTIVE
  There has been increasing use of external beam radiotherapy for localized treatment of hepatocellular carcinoma (HCC) with both palliative and curative intent. Quality control of target delineation in primary HCC is essential to deliver adequate doses of radiation to the primary tumor while preserving adjacent healthy organs. We analyzed interobserver variability in gross tumor volume (GTV) delineation for HCC.
  
  
  METHODS
  Twelve radiation oncologists specializing in liver malignancy participated in a multi-institutional contouring dummy-run study of nine HCC cases and independently delineated GTV on the same set of provided computed tomography images. Quantitative analysis was performed using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE) with kappa statistics calculating agreement between physicians. To quantify the interobserver variability of GTV delineations, the ratio of the actual delineated volume to the estimated consensus volume (STAPLE), the ratio of the common and encompassing volumes, and the coefficient of variation were calculated.
  
  
  RESULTS
  The median kappa agreement level was 0.71 (range 0.28-0.86). The ratio of the actual delineated volume to the estimated consensus volume ranged from 0.19 to 1.93 (median 0.94) for all cases. The ratio of the common and encompassing volumes ranged from 0.001 to 0.56 (median 0.25). The coefficient of variation for GTV delineation ranged from 8 to 57 % (median 26 %).
  
  
  CONCLUSIONS
  The interobserver variability in target delineation of HCC GTV in this study is noteworthy. Multi-institution studies involving radiotherapy for HCC require appropriate quality assurance programs for target delineation.
authors.affiliation: Department of Radiation Oncology, Jeju National University Hospital, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jun Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Ansan Hospital, Korea University Medical Center, Ansan, Korea.
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Yoon
authors.affiliation: Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Min Kyu
authors.initials: MK
authors.lastname: Kang
authors.affiliation: Department of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ik Jae
authors.initials: IJ
authors.lastname: Lee
authors.affiliation: Center for Liver Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Hyung-Sik
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Jang
authors.affiliation: Department of Radiation Oncology, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Chul Seung
authors.initials: CS
authors.lastname: Kay
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Yoon
authors.affiliation: Department of Radiation Oncology, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Mi-Sook
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, 120-752, Seodaemun-gu, Seoul, Korea. jsseong@yuhs.ac.
authors.forename: Jinsil
authors.initials: J
authors.lastname: Seong
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D015203:Reproducibility of Results; D056910:Republic of Korea; D012680:Sensitivity and Specificity; D047368:Tumor Burden
keywords: Chemoembolization; Organs at risk; Quality assurance; Radiofrequency ablation; Radiotherapy