title: A Contralateral Esophagus-Sparing Technique to Limit Severe Esophagitis Associated With Concurrent High-Dose Radiation and Chemotherapy in Patients With Thoracic Malignancies.
abstract: OBJECTIVE
  Severe (Radiation Therapy Oncology Group [RTOG] grade 3 or greater) esophagitis generally occurs in 15% to 25% of non-small cell lung cancer (NSCLC) patients undergoing concurrent chemotherapy and radiation therapy (CCRT), which may result in treatment breaks that compromise local tumor control and pose a barrier to dose escalation. Here, we report a novel contralateral esophagus-sparing technique (CEST) that uses intensity modulated radiation therapy (IMRT) to reduce the incidence of severe esophagitis.
  
  
  METHODS
  We reviewed consecutive patients with thoracic malignancies undergoing curative CCRT in whom CEST was used. The esophageal wall contralateral (CE) to the tumor was contoured as an avoidance structure, and IMRT was used to guide a rapid dose falloff gradient beyond the target volume in close proximity to the esophagus. Esophagitis was recorded based on the RTOG acute toxicity grading system.
  
  
  RESULTS
  We identified 20 consecutive patients treated with CCRT of at least 63 Gy in whom there was gross tumor within 1 cm of the esophagus. The median radiation dose was 70.2 Gy (range, 63-72.15 Gy). In all patients, ≥99% of the planning and internal target volumes was covered by ≥90% and 100% of prescription dose, respectively. Strikingly, no patient experienced grade ≥3 esophagitis (95% confidence limits, 0%-16%) despite the high total doses delivered. The median maximum dose, V45, and V55 of the CE were 60.7 Gy, 2.1 cc, and 0.4 cc, respectively, indicating effective esophagus cross-section sparing by CEST.
  
  
  CONCLUSIONS
  We report a simple yet effective method to avoid exposing the entire esophagus cross-section to high doses. By using proposed CE dose constraints of V45 <2.5 cc and V55 <0.5 cc, CEST may improve the esophagus toxicity profile in thoracic cancer patients receiving CCRT even at doses above the standard 60- to 63-Gy levels. Prospective testing of CEST is warranted.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Hani
authors.initials: H
authors.lastname: Al-Halabi
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Peter
authors.initials: P
authors.lastname: Paetzold
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Sharp
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Christine
authors.initials: C
authors.lastname: Olsen
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: hwillers@mgh.harvard.edu.
authors.forename: Henning
authors.initials: H
authors.lastname: Willers
mesh_terms: D000230:Adenocarcinoma / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000628:therapy; D059248:Chemoradiotherapy / Q000009:adverse effects* / Q000379:methods; D004941:Esophagitis / Q000209:etiology / Q000517:prevention & control*; D004947:Esophagus / Q000000981:diagnostic imaging / Q000528:radiation effects*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000628:therapy; D008297:Male; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000379:methods*; D011832:Radiation Injuries / Q000517:prevention & control*; D011859:Radiography; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D013899:Thoracic Neoplasms / Q000628:therapy*; D013953:Thymus Neoplasms / Q000628:therapy