title: IMRT dose fractionation for head and neck cancer: variation in current approaches will make standardisation difficult.
abstract: BACKGROUND
  Altered fractionation has demonstrated clinical benefits compared to the conventional 2 Gy/day standard of 70 Gy. When using synchronous chemotherapy, there is uncertainty about optimum fractionation. IMRT with its potential for Simultaneous Integrated Boost (SIB) adds further to this uncertainty. This survey will examine international practice of IMRT fractionation and suggest possible reasons for diversity in approach.
  
  
  METHODS
  Fourteen international cancer centres were surveyed for IMRT dose/fractionation practised in each centre.
  
  
  RESULTS
  Twelve different types of dose fractionation were reported. Conventional 70-72 Gy (daily 2 Gy/fraction) was used in 3/14 centres with concurrent chemotherapy while 11/14 centres used altered fractionation. Two centres used >1 schedule. Reported schedules and number of centres included 6 fractions/week DAHANCA regime (3), modest hypofractionation (< or =2.2 Gy/fraction) (3), dose-escalated hypofractionation (> or =2.3 Gy/fraction) (4), hyperfractionation (1), continuous acceleration (1) and concomitant boost (1). Reasons for dose fractionation variability include (i) dose escalation; (ii) total irradiated volume; (iii) number of target volumes; (iv) synchronous systemic treatment; (v) shorter overall treatment time; (vi) resources availability; (vii) longer time on treatment couch; (viii) variable GTV margins; (ix) confidence in treatment setup; (x) late tissue toxicity and (xi) use of lower neck anterior fields.
  
  
  CONCLUSIONS
  This variability in IMRT fractionation makes any meaningful comparison of treatment results difficult. Some standardization is needed particularly for design of multi-centre randomized clinical trials.
authors.affiliation: Academic Department of Radiation Oncology, University of Manchester, Christie Hospital, Wilmslow Road, Manchester, UK.
authors.forename: Kean F
authors.initials: KF
authors.lastname: Ho
authors.forename: Jack F
authors.initials: JF
authors.lastname: Fowler
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sykes
authors.forename: Beng K
authors.initials: BK
authors.lastname: Yap
authors.forename: Lip W
authors.initials: LW
authors.lastname: Lee
authors.forename: Nick J
authors.initials: NJ
authors.lastname: Slevin
mesh_terms: D019583:Dose Fractionation, Radiation; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*