title: A qualitative synthesis of the evidence behind elective lymph node irradiation in oesophageal cancer.
abstract: OBJECTIVE
  Oesophageal cancer is the sixth leading cause of cancer death worldwide and radiotherapy plays a prominent role in its treatment. The presence of lymph node (LN) metastasis has been demonstrated to be one of the most significant prognostic factors related to oesophageal cancer. The use of elective lymph node irradiation (ENI) is still a topic of persistent controversy. The conservative school is to irradiate positive lymph nodes only; the other school is to prophylactically irradiate the regional lymph node area according to different tumour sites. This review investigated the justification for including ENI in the treatment of patients with oesophageal cancer.
  
  
  METHODS
  We performed a systematic literature search to find surgical data about lymph node distribution depending on different tumour subgroups: early, cervical, thoracic and gastroesophageal junction cancer. Furthermore, we performed a qualitative assessment of recurrence patterns in patients treated with or without ENI to derive estimates of the potential area at risk for lymph node harvest.
  
  
  RESULTS
  We identified and reviewed 49 studies: 10 in early, 8 in cervical, 10 in thoracic and the remaining 21 in gastroesophageal junction cancer. In general, these studies were conclusive in incidence and location of pathologic lymph nodes for different subgroups. Data for lymph node recurrence patterns are scarce and contributed little to our review.
  
  
  CONCLUSIONS
  This review resulted in five recommendations for radiation oncologists in daily practice. We used the available evidence about metastatic lymph node distribution to develop a careful reasonable radiation protocol for the corresponding tumour subgroups.
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands. Electronic address: Lien.vandevoorde@maastro.nl.
authors.forename: Lien
authors.initials: L
authors.lastname: Van De Voorde
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Ruben T H M
authors.initials: RT
authors.lastname: Larue
authors.affiliation: Health Insurance Company, CZ, Tilburg, The Netherlands.
authors.forename: Madelon
authors.initials: M
authors.lastname: Pijls
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Buijsen
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Esther G C
authors.initials: EG
authors.lastname: Troost
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Maaike
authors.initials: M
authors.lastname: Berbée
authors.affiliation: Department of Surgery, Atrium Medical Center, Heerlen, The Netherlands.
authors.forename: Meindert
authors.initials: M
authors.lastname: Sosef
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Wouter
authors.initials: W
authors.lastname: van Elmpt
authors.affiliation: Department of Surgery, Atrium Medical Center, Heerlen, The Netherlands.
authors.forename: Marie-Céline
authors.initials: MC
authors.lastname: Schraepen
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Ben
authors.initials: B
authors.lastname: Vanneste
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Michel
authors.initials: M
authors.lastname: Oellers
authors.affiliation: Department of Radiation Oncology (MAASTRO), Maastricht UMC+, The Netherlands.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy; D004938:Esophageal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D000077277:Esophageal Squamous Cell Carcinoma; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy
keywords: Elective; Lymph node; Oesophageal cancer; Radiotherapy; Review; Surgery