title: Performance of the EORTC questionnaire for the assessment of quality of life in head and neck cancer patients EORTC QLQ-H&N35: a methodological review.
abstract: OBJECTIVE
  The EORTC QLQ-H&N35 (H&N35) is widely used to measure quality of life in head and neck cancer patients. The aims of this study were to obtain insight into a) the languages in which the H&N35 has been used and the psychometric properties in those languages, b) the study designs, and c) its acceptance by patients and investigators.
  
  
  METHODS
  A systematic literature review was performed searching for all original papers that had used at least one item of the H&N35. Identified papers were read and the information about methodological issues abstracted statistically analysed.
  
  
  RESULTS
  A total of 136 papers were identified. The H&N35 was administered in 19 different languages in 27 countries. The study design was cross-sectional in the majority of studies (53 %), prospective cohort studies (31 %), phase-II-trials (7 %), phase-III-trials (6 %) and case-control studies (1 %). The scales with the highest percentages of missing values were Sexuality (11.5 %) and Speech (7 %). The median Cronbach's alpha of the multi-item scales ranged from 0.61 (Senses) to 0.93 (Sexuality). Construct validity was rarely investigated. On average, 12 scales (range 0-18) of the instrument were used by the investigators. The scale most often used was swallowing (in 85 % of studies) and least often used was Weight Gain (39 %).
  
  
  CONCLUSIONS
  The H&N35 is widely used throughout the world, mainly in observational studies, and has demonstrated robust psychometric features in different languages. However, some methodological problems reported imply that the instrument can be improved in some areas.
authors.affiliation: Institute of Medical Biostatistics, Epidemiology, and Informatics, University of Mainz, Obere Zahlbacher Str. 69, 55131, Mainz, Germany, susanne.singer@unimedizin-mainz.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Singer
authors.forename: Juan Ignacio
authors.initials: JI
authors.lastname: Arraras
authors.forename: Wei-Chu
authors.initials: WC
authors.lastname: Chie
authors.forename: Sheila E
authors.initials: SE
authors.lastname: Fisher
authors.forename: Razvan
authors.initials: R
authors.lastname: Galalae
authors.forename: Eva
authors.initials: E
authors.lastname: Hammerlid
authors.forename: Ourania
authors.initials: O
authors.lastname: Nicolatou-Galitis
authors.forename: Claudia
authors.initials: C
authors.lastname: Schmalz
authors.forename: Irma
authors.initials: I
authors.lastname: Verdonck-de Leeuw
authors.forename: Eva
authors.initials: E
authors.lastname: Gamper
authors.forename: Judith
authors.initials: J
authors.lastname: Keszte
authors.forename: Dirk
authors.initials: D
authors.lastname: Hofmeister
mesh_terms: D006258:Head and Neck Neoplasms / Q000523:psychology*; D006305:Health Status Indicators; D006801:Humans; D007802:Language; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D015203:Reproducibility of Results; D012107:Research Design; D012680:Sensitivity and Specificity; D012725:Sexual Behavior; D011795:Surveys and Questionnaires / Q000592:standards*