title: Recurrence pattern of squamous cell carcinoma in the midthoracic esophagus: implications for the clinical target volume design of postoperative radiotherapy.
abstract: BACKGROUND
  Postoperative radiotherapy has shown positive efficacy in lowering the recurrence rate and improving the survival rate for patients with esophageal squamous cell carcinoma (ESCC). However, controversies still exist about the postoperative prophylactic radiation target volume. This study was designed to analyze the patterns of recurrence and to provide a reference for determination of the postoperative radiotherapy target volume for patients with midthoracic ESCC.
  
  
  METHODS
  A total of 338 patients with recurrent or metastatic midthoracic ESCC after radical surgery were retrospectively examined. The patterns of recurrence including locoregional and distant metastasis were analyzed for these patients.
  
  
  RESULTS
  The rates of lymph node (LN) metastasis were 28.4% supraclavicular, 77.2% upper mediastinal, 32.0% middle mediastinal, 50.0% lower mediastinal, and 19.5% abdominal LNs. In subgroup analyses, the rate of abdominal LN metastasis was significantly higher in patients with histological node-positive than that in patients with histological node-negative (P=0.033). Further analysis in patients with histological node-positive demonstrated that patients with three or more positive nodes are more prone to abdominal LN metastasis, compared with patients with one or two positive nodes (χ2=4.367,P=0.037). The length of tumor and histological differentiation were also the high-risk factors for abdominal LN metastasis.
  
  
  CONCLUSIONS
  For midthoracic ESCC with histological node-negative, or one or two positive nodes, the supraclavicular and stations 2, 4, 5, and 7 LNs should be delineated as clinical target volume of postoperative prophylactic irradiation, and upper abdominal LNs should be excluded. While for midthoracic ESCC with three or more positive nodes, upper abdominal LNs should also be included. The length of tumor and histological differentiation should be considered comprehensively to design the clinical target volume for radiotherapy.
authors: School of Medicine and Life Sciences, Jinan University-Shandong Academy of Medical Sciences, Jinan, Shandong, People's Republic of China; Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Xiaoli
authors: X
authors: Wang
authors: School of Medicine and Life Sciences, Jinan University-Shandong Academy of Medical Sciences, Jinan, Shandong, People's Republic of China; Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Yijun
authors: Y
authors: Luo
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Minghuan
authors: M
authors: Li
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Hongjiang
authors: H
authors: Yan
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Mingping
authors: M
authors: Sun
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong, People's Republic of China.
authors: Tingyong
authors: T
authors: Fan
keywords: clinical target volume; esophagus cancer; radiotherapy; recurrence and metastasis