title: Comparative treatment planning study on sequential vs. simultaneous integrated boost in head and neck cancer patients: Differences in dose distributions and potential implications for clinical practice.
abstract: OBJECTIVE
  The purpose of this work was to compare sequential (SeqB) versus simultaneous integrated boost (SIB) radiotherapy plans delivered with volumetric modulated arc therapy (VMAT) for patients with locally advanced squamous cell cancer of the head and neck (HNSCC).
  
  
  METHODS
  SeqB and SIB plans using VMAT for 10 HNSCC patients given definitive chemoradiation were generated and analysed for differences in dose distribution, coverage, conformity and homogeneity to the planning target volumes (PTV) 1-3 and sparing of organs at risk (OAR).
  
  
  RESULTS
  The mean delineated volumes ± standard deviations were 137.7 ± 44.8, 351.3 ± 83.9 and 895.6 ± 120.5 cm3 for PTV1-3. The mean volumes encompassed by the corresponding 95 % isodoses were 281 (+ 110 %) ± 73.4, 712.2 (+ 115 %) ± 146.4 and 1381.1 (+ 54 %) ± 217.3 cm3 with SeqB and 138.2 (+ 7 %) ± 40.1, 380.4 (+ 11 %) ± 91.9 and 1057.3 (+ 21 %) ± 161.4 cm3 with SIB for PTV1-3, respectively. Both strategies achieved excellent PTV coverage. SeqB provided significantly better coverage of PTV1 and 3, worse conformity for PTV1-3 and a higher mean dose than prescribed (111-115 %) to PTV2 and 3 (p ≤ 0.007). Both strategies provided satisfactory OAR sparing.
  
  
  CONCLUSIONS
  This study showed significant dosimetric differences with potential clinical relevance between two VMAT boost strategies regarding coverage, conformity and dose to the PTVs. SIB might cause less toxicity. A clinical phase III/IV trial endorsed by the German Head and Neck Clinical Trials Group (IAG-KHT) will evaluate differences in acute/late toxicity as well as in locoregional recurrences between the two boost techniques.
authors.forename: Carmen
authors.initials: C
authors.lastname: Stromberger
authors.forename: Pirus
authors.initials: P
authors.lastname: Ghadjar
authors.forename: Simone
authors.initials: S
authors.lastname: Marnitz
authors.forename: Alexander Henry
authors.initials: AH
authors.lastname: Thieme
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jahn
authors.forename: Jan D
authors.initials: JD
authors.lastname: Raguse
authors.forename: Evis
authors.initials: E
authors.lastname: Karaj-Rossbacher
authors.forename: Arne
authors.initials: A
authors.lastname: Böttcher
authors.forename: Basil
authors.initials: B
authors.lastname: Jamil
authors.forename: Volker
authors.initials: V
authors.lastname: Budach
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D059248:Chemoradiotherapy / Q000379:methods*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010039:Otorhinolaryngologic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D010347:Patient Care Planning; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*