title: Long-term experience with reduced planning target volume margins and intensity-modulated radiotherapy with daily image-guidance for head and neck cancer.
abstract: BACKGROUND
  The purpose of this study was to compare outcomes among patients treated by intensity-modulated radiotherapy (IMRT) with daily image-guided radiotherapy (IGRT) for head and neck cancer according to the margins used to expand the clinical target volume (CTV) to create a planning target volume (PTV).
  
  
  METHODS
  Three hundred sixty-seven consecutive patients were treated with IMRT for squamous cell carcinoma of the head and neck. The first 103 patients were treated with 5-mm CTV-to-PTV margins. The subsequent 264 patients were treated using reduced (3 mm) margins.
  
  
  RESULTS
  The 3-year locoregional control for patients treated using 5-mm and 3-mm CTV-to-PTV margins, respectively, was 78% and 80% (p = .75). The incidence of gastrostomy-tube dependence at 1 year was 10% and 3%, respectively (p = .001). The incidence of posttreatment esophageal stricture was 14% and 7%, respectively (p = .01).
  
  
  CONCLUSIONS
  The use of reduced (3 mm) CTV-to-PTV margins was associated with reduced late toxicity while maintaining locoregional control.
authors.affiliation: Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, California.
authors.forename: Allen M
authors.initials: AM
authors.lastname: Chen
authors.forename: Yao
authors.initials: Y
authors.lastname: Yu
authors.forename: Megan E
authors.initials: ME
authors.lastname: Daly
authors.forename: D Gregory
authors.initials: DG
authors.lastname: Farwell
authors.forename: Stanley H
authors.initials: SH
authors.lastname: Benedict
authors.forename: James A
authors.initials: JA
authors.lastname: Purdy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D015331:Cohort Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D000077195:Squamous Cell Carcinoma of Head and Neck; D016896:Treatment Outcome; D055815:Young Adult
keywords: head and neck cancer; image-guided radiotherapy; intensity-modulated radiotherapy; marginal misses; planning target volume