title: Selective omission of level V nodal coverage for patients with oropharyngeal cancer: Clinical validation of intensity-modulated radiotherapy experience and dosimetric significance.
abstract: BACKGROUND
  We sought to validate the consensus recommendation and assess dosimetric significance of selective omission of nodal level V from intensity-modulated radiotherapy (IMRT) clinical target volume (CTV) for oropharyngeal cancer.
  
  
  METHODS
  IMRT plans and clinical outcomes for 112 patients with oropharyngeal cancer (nodal classification N0-N2b) were analyzed for coverage of ipsilateral and contralateral nodal level V. Additionally, new IMRT plans were generated in 6 randomly selected patients to assess its dosimetric impact.
  
  
  RESULTS
  With median follow-up of 3.4 years, there were no failures identified in nodal level V with or without nodal level V omission. Upon dosimetric evaluation, significant reduction in integral dose, V10 Gy , V20 Gy , V30 Gy , V40 Gy , and V50 Gy was observed by excluding unilateral and bilateral level V from the CTV.
  
  
  CONCLUSIONS
  We clinically validate the consensus recommendation for selective omission of level V nodal coverage in IMRT planning of patients with oropharyngeal cancer and demonstrate significant dosimetric advantages.
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.|Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Pranshu
authors.identifier: http://orcid.org/0000-0002-4873-7496
authors.initials: P
authors.lastname: Mohindra
authors.affiliation: Department of Radiation Oncology, Aurora Cancer Center, Grafton, Wisconsin.
authors.forename: Erich
authors.initials: E
authors.lastname: Urban
authors.affiliation: University of Arkansas for Medical Sciences, College of Medicine, Little Rock, Arkansas.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Pagan
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Geye
authors.affiliation: University of Connecticut, School of Medicine, Farmington, Connecticut.
authors.forename: Vatsal B
authors.initials: VB
authors.lastname: Patel
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: R Adam A
authors.initials: RA
authors.lastname: Bayliss
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Bender
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Harari
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009959:Oropharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011874:Radiometry; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis; D016896:Treatment Outcome
keywords: intensity-modulated radiotherapy (IMRT); level V; neck lymph nodes; oropharyngeal cancer; patterns of failure