title: The effect on esophagus after different radiotherapy techniques for early stage Hodgkin's lymphoma.
abstract: BACKGROUND
  The cure rate of early stage Hodgkin's lymphoma (HL) is excellent; investigating the late effects of treatment is thus important. Esophageal toxicity is a known side effect in patients receiving radiotherapy (RT) to the mediastinum, although little is known of this in HL survivors. This study investigates the dose to the esophagus in the treatment of early stage HL using different RT techniques. Estimated risks of early esophagitis, esophageal stricture and cancer are compared between treatments.
  
  
  METHODS
  We included 46 patients ≥ 15 years with supradiaphragmatic, clinical stage I-II HL, who received chemotherapy followed by involved node RT (INRT) to 30.6 Gy at our institution. INRT was planned with three-dimensional conformal RT (3DCRT). For each patient a volumetric modulated arc therapy (VMAT), proton therapy (PT) and mantle field (MF) treatment plan was simulated. Mean, maximum and minimum dose to the esophagus were extracted from the treatment plans. Risk estimates were based on dose-response models from clinical series with long-term follow-up. Statistical analyses were performed with repeated measures ANOVA using Bonferroni corrections.
  
  
  RESULTS
  Mean dose to the esophagus was 16.4, 16.4, 14.7 and 34.2 Gy (p < 0.001) with 3DCRT, VMAT, PT and MF treatment, respectively. No differences were seen in the estimated risk of developing esophagitis, stricture or cancer with 3DCRT compared to VMAT (p = 1.000, p = 1.000, p = 0.356). PT performed significantly better with the lowest risk estimates on all parameters compared to the photon treatments, except compared to 3DCRT for stricture (p = 0.066). On all parameters the modern techniques were superior to MF treatment (p < 0.001).
  
  
  CONCLUSIONS
  The estimated dose to the esophagus and the corresponding estimated risks of esophageal complications are decreased significantly with highly conformal RT compared to MF treatment. The number of patients presenting with late esophageal side effects will, thus, likely be minimal in the future.
authors.affiliation: Department of Radiation Oncology, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Anni Y S
authors.initials: AY
authors.lastname: Jørgensen
authors.forename: Maja V
authors.initials: MV
authors.lastname: Maraldo
authors.forename: Nils Patrik
authors.initials: NP
authors.lastname: Brodin
authors.forename: Marianne C
authors.initials: MC
authors.lastname: Aznar
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Vogelius
authors.forename: Per Munck Af
authors.initials: PM
authors.lastname: Rosenschöld
authors.forename: Peter M
authors.initials: PM
authors.lastname: Petersen
authors.forename: Lena
authors.initials: L
authors.lastname: Specht
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004941:Esophagitis / Q000175:diagnosis / Q000209:etiology*; D004947:Esophagus / Q000473:pathology / Q000528:radiation effects*; D005260:Female; D006689:Hodgkin Disease / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D058958:Organs at Risk / Q000528:radiation effects*; D011379:Prognosis; D061766:Proton Therapy / Q000009:adverse effects*; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed; D055815:Young Adult