title: Assessment of radiation-induced xerostomia: validation of the Italian version of the xerostomia questionnaire in head and neck cancer patients.
abstract: OBJECTIVE
  Xerostomia is the most common acute and late side effect of radiation treatment for head and neck cancer. Affecting taste perception, chewing, swallowing and speech, xerostomia is also the major cause of decreased quality of life. The aims of this study were to validate the Italian translation of the self-reported eight-item xerostomia questionnaire (XQ) and determine its psychometric properties in patients treated with radiotherapy for head and neck cancer.
  
  
  METHODS
  An observational cross-sectional study was conducted in the Radiotherapy Unit of the Veneto Institute of Oncology - IOV in Padua. The XQ was translated according to international guidelines and filled out by 102 patients. Construct validity was assessed using principal component analysis, internal consistency using Cronbach's α coefficient and test-retest reliability at 1-month interval using the intraclass correlation coefficient (ICC). Criterion-related validity was evaluated to compare the Italian version of XQ with the European Organization for Research and Treatment of Cancer (EORTC) Core Quality-of-Life Questionnaire (QLQ-C30) and its Head and Neck Cancer Module (QLQ-H&N35).
  
  
  RESULTS
  Cronbach's α for the Italian version of XQ was strong at α = 0.93, test-retest reliability was also strong (0.79) and factor analysis confirmed that the questionnaire was one-dimensional. Criterion-related validity was excellent with high association with the EORTC QLQ-H&N35 xerostomia and sticky saliva scales.
  
  
  CONCLUSIONS
  The Italian version of XQ has excellent psychometric properties and can be used to evaluate the impact of emerging radiation delivery techniques aiming at preventing xerostomia.
authors.affiliation: Radiotherapy Unit, Veneto Institute of Oncology IOV - IRCCS, Via Gattamelata, 64, 35128, Padova, Italy, federica.pellegrino@ioveneto.it.
authors.forename: Federica
authors.initials: F
authors.lastname: Pellegrino
authors.forename: Elena
authors.initials: E
authors.lastname: Groff
authors.forename: Luca
authors.initials: L
authors.lastname: Bastiani
authors.forename: Bruno
authors.initials: B
authors.lastname: Fattori
authors.forename: Guido
authors.initials: G
authors.lastname: Sotti
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007558:Italy; D007802:Language; D008297:Male; D011594:Psychometrics; D011788:Quality of Life; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology; D011878:Radiotherapy / Q000009:adverse effects*; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires / Q000592:standards*; D014177:Translations; D014987:Xerostomia / Q000175:diagnosis* / Q000209:etiology