title: Interobserver variability in the delineation of the tumour bed using seroma and surgical clips based on 4DCT scan for external-beam partial breast irradiation.
abstract: BACKGROUND
  To explore the interobserver variability in the delineation of the tumour bed using seroma and surgical clips based on the four-dimensional computed tomography (4DCT) scan for external-beam partial breast irradiation (EB-PBI) during free breathing.
  
  
  METHODS
  Patients with a seroma clarity score (SCS) 3 ~ 5 and ≥5 surgical clips in the lumpectomy cavity after breast-conserving surgery who were recruited for EB-PBI underwent 4DCT simulation. Based on the ten sets of 4DCT images acquired, the tumour bed formed using the clips, the seroma, and both the clips and seroma (defined as TBC, TBS and TBC+S, respectively) were delineated by five radiation oncologists using specific guidelines. The following parameters were calculated to analyse interobserver variability: volume of the tumour bed (TBC, TBS, TBC+S), coefficient of variation (COVC, COVS, COVC+S), and matching degree (MDC, MDS, MDC+S).
  
  
  RESULTS
  The interobserver variability for TBC and TBC+S and for COVC and COVC+S were statistically significant (p = 0.021, 0.008, 0.002, 0.015). No significant difference was observed for TBS and COVS (p = 0.867, 0.061). Significant differences in interobserver variability were observed for MDC vs MDS, MDC vs MDC+S, MDS vs MDC+S (p = 0.000, 0.032, 0.008), the interobserver variability of MDS was smaller than that of MDC and MDC+S (MDS > MDC+S > MDC).
  
  
  CONCLUSIONS
  When the SCS was 3 ~ 5 points and the number of surgical clips was ≥5, interobserver variability was minimal for the delineation of the tumour bed based on seroma.
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. guobing9541@163.com.|Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan, Shandong Province, People's Republic of China. guobing9541@163.com.
authors.forename: Bing
authors.initials: B
authors.lastname: Guo
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. lijianbin@msn.com.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. w.wei1103@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. xumin7799@hotmail.com.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. shaoqian2009@sina.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. flyingguy18@sina.com.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. 1114195472@qq.com.
authors.forename: Chaoqian
authors.initials: C
authors.lastname: Liang
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jiyan Road, Jinan, Shandong Province, 250117, China. cinderalla3@163.com.|Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan, Shandong Province, People's Republic of China. cinderalla3@163.com.
authors.forename: Yanluan
authors.initials: Y
authors.lastname: Guo
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D009367:Neoplasm Staging; D015588:Observer Variation; D011379:Prognosis; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D049291:Seroma / Q000473:pathology*; D013525:Surgical Instruments; D047368:Tumor Burden