title: Volumetric modulated arc therapy (VMAT) and simultaneous integrated boost in head-and-neck cancer: is there a place for critical swallowing structures dose sparing?
abstract: OBJECTIVE
  To explore the potential of volumetric-modulated arc therapy (VMAT) to reduce the risk of swallowing problems after curative chemoradiotherapy.
  
  
  METHODS
  20 patients with head and neck cancer who previously underwent radiotherapy were selected. Radiotherapy was prescribed according to simultaneous integrated boost technique with all targets irradiated simultaneously over 30 daily fractions. Doses of 70.5 (67.5), 60.0 and 55.5 Gy were prescribed to primary tumour, high-risk nodal regions and low-risk nodal regions, respectively. Pharyngeal constrictor muscles (PCM) and glottic and supraglottic larynx (SGL) were considered organs at risk related to swallowing dysfunction (SW-OARs). Upper pharyngeal constrictor muscles (uPCM), middle pharyngeal constrictor muscles (mPCM) and lower pharyngeal constrictor muscles (lPCM) part of PCM were also outlined separately. Clinical standard plans (standard-VMAT) and plans aiming to spare SW-OARs (swallowing dysfunction-VMAT) were also created. Normal tissue complication probabilities (NTCP) for physician-rated swallowing dysfunction were calculated using a recently predictive model developed by Christianen et al.
  
  
  RESULTS
  Planning with two strategies demonstrated comparable planning target volume coverage and no differences in sparing of parotid glands and other non-swallowing organs at risk. SW-VMAT plans provided mean dose reduction for uPCM and SGL by 3.9 and 4.5 Gy, respectively. NTCP values for Radiation Therapy Oncology Group grade 2-4 swallowing dysfunction was decreased by 9.2%. Dose reductions with SW-VMAT depended on tumour location and overlap with SW-OARs.
  
  
  CONCLUSIONS
  VMAT plans aiming at sparing swallowing structures are feasible, providing a significant reduction in NTCP swallowing dysfunction with respect to conventional VMAT.
  
  
  CONCLUSIONS
  Dysphagia is today considered one of the dose-limiting toxicities of chemoradiotherapy. The dose sparing of swallowing structures represents a major challenge in radiotherapy. VMAT is a complex new technology having the potential to significantly reduce the risk of dysphagia after curative chemoradiotherapy.
authors.affiliation: 1 Medical Physics Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Universit à Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Savino
authors.initials: S
authors.lastname: Cilla
authors.affiliation: 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Università Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Deodato
authors.affiliation: 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Università Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Macchia
authors.affiliation: 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Università Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Digesù
authors.affiliation: 1 Medical Physics Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Universit à Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Ianiro
authors.affiliation: 3 Medical Physics Unit, Policlinico Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Piermattei
authors.affiliation: 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Università Cattolica del Sacro Cuore, Campobasso, Italy.|4 Radiotherapy Department, Policlinico Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Valentini
authors.affiliation: 5 DIMES Università di Bologna-S.Orsola-Malpighi Hospital, Radiation Oncology Center, Bologna, Italy.
authors.forename: Alessio G
authors.initials: AG
authors.lastname: Morganti
mesh_terms: D003679:Deglutition / Q000528:radiation effects*; D003680:Deglutition Disorders / Q000517:prevention & control*; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D058958:Organs at Risk; D010614:Pharynx / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated