title: Intensity-modulated radiotherapy significantly reduces xerostomia compared with conventional radiotherapy.
abstract: OBJECTIVE
  Xerostomia is a severe complication after radiotherapy for oropharyngeal cancer, as the salivary glands are in close proximity with the primary tumor. Intensity-modulated radiotherapy (IMRT) offers theoretical advantages for normal tissue sparing. A Phase II study was conducted to determine the value of IMRT for salivary output preservation compared with conventional radiotherapy (CRT).
  
  
  METHODS
  A total of 56 patients with oropharyngeal cancer were prospectively evaluated. Of these, 30 patients were treated with IMRT and 26 with CRT. Stimulated parotid salivary flow was measured before, 6 weeks, and 6 months after treatment. A complication was defined as a stimulated parotid flow rate <25% of the preradiotherapy flow rate.
  
  
  RESULTS
  The mean dose to the parotid glands was 48.1 Gy (SD 14 Gy) for CRT and 33.7 Gy (SD 10 Gy) for IMRT (p < 0.005). The mean parotid flow ratio 6 weeks and 6 months after treatment was respectively 41% and 64% for IMRT and respectively 11% and 18% for CRT. As a result, 6 weeks after treatment, the number of parotid flow complications was significantly lower after IMRT (55%) than after CRT (87%) (p = 0.002). The number of complications 6 months after treatment was 56% for IMRT and 81% for CRT (p = 0.04).
  
  
  CONCLUSIONS
  IMRT significantly reduces the number of parotid flow complications for patients with oropharyngeal cancer.
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands. P.M.Braam@umcutrecht.nl
authors.forename: Pètra M
authors.initials: PM
authors.lastname: Braam
authors.forename: Chris H J
authors.initials: CH
authors.lastname: Terhaard
authors.forename: Judith M
authors.initials: JM
authors.lastname: Roesink
authors.forename: Cornelis P J
authors.initials: CP
authors.lastname: Raaijmakers
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000150:complications / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology* / Q000517:prevention & control*; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome; D014987:Xerostomia / Q000209:etiology* / Q000517:prevention & control*