title: Comprehensive head and neck radiotherapy dose-volume constraints do not apply to smaller volumes.
abstract: OBJECTIVE
  To investigate the impact of definitive radiation therapy (RT) in the management of early glottic cancer on clinical RT-induced dysphagia (RID) and carotid vasculopathy (RICV).
  
  
  METHODS
  This is a single-institution retrospective study. From January 1997 to 2010, 253 patients, with early glottic cancer, underwent RT with (60)Co or LINAC-6 MV photons. RT fields with wedge pair and daily 5-mm bolus were applied in all patients treated with 6-MV photons to avoid under-dose of the anterior laryngeal structures. The whole larynx (LX), pharyngeal constrictors (PCs), and carotid arteries (CA) were contoured and dose-volume histograms (DVHs) were generated to assess the delivered dose. The median age of patients was 65 years (range; 28-93), Caucasians were 80%, males were 87%, and 23% had T2 lesions.
  
  
  RESULTS
  After a median follow-up of seven years (range; 1.5-12), the median dose and fraction size delivered to the LX were 63 and 2.25 Gy, respectively. The mean doses to the LX, PC, and CA were 57 Gy delivered to 34 cm(3), 54 Gy to 15 cm(3), and 60 Gy to 4 cm(3), respectively. The LX, PC and CA V60 and V65 were (77 and 71), (70 and 52) and (84 and 51), respectively. Patients with acute dysphagia grades 1, 2, and 3 or more were 81, 19%, and zero, respectively; none had clinically RID or RICV.
  
  
  CONCLUSIONS
  Small-volume RT up to 67.5 Gy at 2.25 Gy per fraction, is not a predictor of RID or RICV. Separate delineation of the aforementioned critical structures, as well as others, may better identify dose tolerances to maintain function and further prioritize the importance of structures in RID and RICV.
authors.affiliation: Department of Radiation Oncology, Beth Israel Medical Center, New York, NY, 10 Union Square E. Suite 4 G, New York, 10003, NY, U.S.A. waleed246@gmail.com.
authors.forename: Waleed F
authors.initials: WF
authors.lastname: Mourad
authors.forename: Daniel
authors.initials: D
authors.lastname: Shasha
authors.forename: Dukagjin M
authors.initials: DM
authors.lastname: Blakaj
authors.forename: Azita S
authors.initials: AS
authors.lastname: Khorsandi
authors.forename: Rania A
authors.initials: RA
authors.lastname: Shourbaji
authors.forename: Jonathan
authors.initials: J
authors.lastname: Glanzman
authors.forename: Rafi
authors.initials: R
authors.lastname: Kabarriti
authors.forename: Rebekah
authors.initials: R
authors.lastname: Young
authors.forename: Shyamal
authors.initials: S
authors.lastname: Patel
authors.forename: Evangelia
authors.initials: E
authors.lastname: Katsoulakis
authors.forename: Mauricio
authors.initials: M
authors.lastname: Gámez
authors.forename: Rudolph
authors.initials: R
authors.lastname: Woode
authors.forename: Cathy
authors.initials: C
authors.lastname: Lazarus
authors.forename: Catherine
authors.initials: C
authors.lastname: Concert
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Hu
authors.forename: Louis B
authors.initials: LB
authors.lastname: Harrison
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D002340:Carotid Artery Diseases / Q000209:etiology; D003680:Deglutition Disorders / Q000209:etiology; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000209:etiology; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden; D014827:Vocal Cords / Q000473:pathology
keywords: Radiation induced dysphagia; carotidvasculopathy; constrictors; early glottic cancer; radiation therapy