title: Preservation of parotid function with uncomplicated conformal radiotherapy.
abstract: OBJECTIVE
  To evaluate (1) parotid function, (2) subjective xerostomia and (3) pattern of relapses after conformal parotid-sparing radiotherapy (RT) for head and neck cancer. (4) To study dose-response curves of parotid glands.
  
  
  METHODS
  From September 1999 to November 2000, 39 head and neck cancer patients requiring bilateral neck RT were treated with a fairly simple conformal RT technique (three-field set-up+anterior lower neck field; two opposed oblique boost fields). The contralateral parotid was spared. Parotid function was assessed by salivary gland scintigraphies performed before, early (median 4 weeks) and late (median 28 weeks) after RT. Xerostomia was monitored by visual analogue scales (VAS) and LENT SOMA scores. Location of locoregional recurrences was studied in relation to the radiation fields. A dose-response curve of parotids was created using logistic regression.
  
  
  RESULTS
  (1) Early after RT, on salivary gland scintigraphy, the mean loss of secretion function in the spared parotid was 67% and total in the non-spared. Late after RT, the mean loss remained 19% in the spared and total in the non-spared parotid. Normal excretion function was regained in 75% of the spared parotids. (2) Late after RT, 78% of patients had no, minimal or acceptable subjective xerostomia. (3) No recurrence was seen near the spared parotid (11/39 locoregional recurrences). (4) The dose-response curve of parotids showed that the mean parotid dose should preferentially be < or =20 Gy, to obtain a good chance (> or =70%) for preservation of its function on scintigraphy.
  
  
  CONCLUSIONS
  An easy conformal parotid-sparing RT technique prevents moderate or severe subjective xerostomia in 78% of patients. In the spared parotids, nearly complete to complete recovery is obtained after 6-12 months.
authors.affiliation: Department of Radiation Oncology, University Hospital Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: Maes
authors.forename: Caroline
authors.initials: C
authors.lastname: Weltens
authors.forename: Patrick
authors.initials: P
authors.lastname: Flamen
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
authors.forename: Ria
authors.initials: R
authors.lastname: Bogaerts
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.forename: Jan
authors.initials: J
authors.lastname: Baetens
authors.forename: Robert
authors.initials: R
authors.lastname: Hermans
authors.forename: Walter
authors.initials: W
authors.lastname: Van den Bogaert
mesh_terms: D000328:Adult; D000368:Aged; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000000981:diagnostic imaging / Q000378:metabolism / Q000528:radiation effects*; D011832:Radiation Injuries / Q000517:prevention & control; D011877:Radionuclide Imaging; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012463:Saliva / Q000378:metabolism; D014987:Xerostomia / Q000209:etiology