title: Radiotherapy for unresectable sinonasal cancers: dosimetric comparison of intensity modulated radiation therapy with coplanar and non-coplanar volumetric modulated arc therapy.
abstract: OBJECTIVE
  To compare volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) plans for treatment of unresectable paranasal sinuses cancers (PNSCs) with different clinical presentations.
  
  
  METHODS
  Four patients treated for primary target volume only (group 1), four requiring elective nodal irradiation (group 2) and four with positive nodes in macroscopic disease (group 3) were selected. For each patient were generated 7 fields IMRT, coplanar VMAT (c-VMAT) and non-coplanar VMAT (nc-VMAT) treatment plans. Total doses were 70Gy and 54Gy to high dose planning target volume (HD-PTV) and low-dose-PTV, respectively. Dose-volume histogram, conformity and homogeneity index (CI and HI), and monitor units (MUs) per Gy were evaluated.
  
  
  RESULTS
  VMAT provided significantly better target coverage, in terms of V100% (Volume encompassed by the isodose 100%), than IMRT, in particular when nc-VMAT was used. In general, organ at risk sparing is similar with the three approaches, although nc-VMAT can allow a statistically significant reduction of dose to contralateral parotid gland and cochlea for all three groups.
  
  
  CONCLUSIONS
  VMAT can offer significant improvement of treatment for all unresectable PNSCs over existing IMRT techniques. In particular, nc-VMAT may be a further advantage for those patients with sinonasal cancers and involvement of the nodes in whom large volumes and complex/irregular shape have to be irradiated, even if clinical benefits should be established in the future.
authors.affiliation: Unit of Radiotherapy 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. Electronic address: ester.orlandi@istitutotumori.mi.it.
authors.forename: Ester
authors.initials: E
authors.lastname: Orlandi
authors.affiliation: Unit of Medical Physics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Giandini
authors.affiliation: Unit of Radiotherapy 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Eva
authors.initials: E
authors.lastname: Iannacone
authors.affiliation: Unit of Medical Physics, A.O. San Gerardo, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: De Ponti
authors.affiliation: Unit of Medical Physics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Carrara
authors.affiliation: Unit of Medical Physics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Mongioj
authors.affiliation: Unit of Medical Physics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Stucchi
authors.affiliation: Unit of Radiotherapy 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Tana
authors.affiliation: Unit of Head and Neck Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bossi
authors.affiliation: Unit of Head and Neck Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Lisa
authors.initials: L
authors.lastname: Licitra
authors.affiliation: Unit of Radiotherapy 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Fallai
authors.affiliation: Unit of Medical Physics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Pignoli
mesh_terms: D006801:Humans; D010255:Paranasal Sinus Neoplasms / Q000532:radiotherapy*; D011874:Radiometry / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
keywords: Dosimetric comparison; Intensity modulated radiation therapy; Normal tissue sparing; Target coverage; Unresectable paranasal sinus cancer; Volumetric modulated arc therapy