title: Dosimetric factors associated with long-term dysphagia after definitive radiotherapy for squamous cell carcinoma of the head and neck.
abstract: OBJECTIVE
  Intensification of radiotherapy and chemotherapy for head-and-neck cancer may lead to increased rates of dysphagia. Dosimetric predictors of objective findings of long-term dysphagia were sought.
  
  
  METHODS
  From an institutional database, 83 patients were identified who underwent definitive intensity-modulated radiotherapy for squamous cell carcinoma of the head and neck, after exclusion of those who were treated for a second or recurrent head-and-neck primary lesion, had locoregional recurrence at any time, had less than 12 months of follow-up, or had postoperative radiotherapy. Dosimetric parameters were analyzed relative to three objective endpoints as a surrogate for severe long-term dysphagia: percutaneous endoscopic gastrostomy (PEG) tube dependence at 12 months, aspiration on modified barium swallow, or pharyngoesophageal stricture requiring dilation.
  
  
  RESULTS
  Mean dose greater than 41 Gy and volume receiving 60 Gy (V(60)) greater than 24% to the larynx were significantly associated with PEG tube dependence and aspiration. V(60) greater than 12% to the inferior pharyngeal constrictor was also significantly associated with increased PEG tube dependence and aspiration. V(65) greater than 33% to the superior pharyngeal constrictor or greater than 75% to the middle pharyngeal constrictor was associated with pharyngoesophageal stricture requiring dilation.
  
  
  CONCLUSIONS
  Doses to the larynx and pharyngeal constrictors predicted long-term swallowing complications, even when controlled for other clinical factors. The addition of these structures to intensity-modulated radiotherapy optimization may reduce the incidence of dysphagia, although cautious clinical validation is necessary.
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL 35249, USA.
authors.forename: Jimmy J
authors.initials: JJ
authors.lastname: Caudell
authors.forename: Philip E
authors.initials: PE
authors.lastname: Schaner
authors.forename: Renee A
authors.initials: RA
authors.lastname: Desmond
authors.forename: Ruby F
authors.initials: RF
authors.lastname: Meredith
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Spencer
authors.forename: James A
authors.initials: JA
authors.lastname: Bonner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D002404:Catheterization / Q000706:statistics & numerical data; D003679:Deglutition; D003680:Deglutition Disorders / Q000209:etiology*; D004940:Esophageal Stenosis / Q000209:etiology / Q000628:therapy; D005260:Female; D005774:Gastrostomy / Q000706:statistics & numerical data; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010608:Pharyngeal Diseases / Q000209:etiology / Q000628:therapy; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult