title: Exploratory Factor Analysis of NRG Oncology's University of Washington Quality of Life Questionnaire-RTOG Modification.
abstract: The 15-item University of Washington Quality of Life questionnaire-Radiation Therapy Oncology Group (RTOG) modification (UW-QOL-RTOG modification) has been used in several trials of head and neck cancer conducted by NRG Oncology such as RTOG 9709, RTOG 9901, RTOG 0244, and RTOG 0537.
  
  
  
  This study is an exploratory factor analysis (EFA) to establish validity and reliability of the instrument subscales.
  
  
  
  EFA on the UW-QOL-RTOG modification was conducted using baseline data from NRG Oncology's RTOG 0537, a trial of acupuncture-like transcutaneous electrical nerve stimulation in treating radiation-induced xerostomia. Cronbach α coefficient was calculated to measure reliability; correlation with the University of Michigan Xerostomia Related Quality of Life Scale was used to evaluate concurrent validity; and correlations between consecutive time points were used to assess test-retest reliability.
  
  
  
  The 15-item EFA of the modified tool resulted in 11 items split into four factors: mucus, eating, pain, and activities. Cronbach α ranged from 0.71 to 0.93 for the factors and total score, consisting of all 11 items. There were strong correlations (ρ ≥ 0.60) between consecutive time points and between total score and the Xerostomia Related Quality of Life Scale total score (ρ > 0.65).
  
  
  
  The UW-QOL-RTOG modification is a valid tool that can be used to assess symptom burden of head and neck cancer patients receiving radiation therapy or those who have recently completed radiation. The modified tool has acceptable reliability, concurrent validity, and test-retest reliability in this patient population, as well as the advantage of having being shortened from 15 to 11 items.
authors.affiliation: NRG Oncology Statistics and Data Management Center, Philadelphia, Pennsylvania, USA. Electronic address: pughs@nrgoncology.org.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Pugh
authors.affiliation: Michigan State University, East Lansing, Michigan, USA.
authors.forename: Gwen
authors.initials: G
authors.lastname: Wyatt
authors.affiliation: Juravinski Cancer Centre, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Raimond K W
authors.initials: RK
authors.lastname: Wong
authors.affiliation: Juravinski Cancer Centre, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Sagar
authors.affiliation: University of Minnesota/Masonic Cancer Center, Minneapolis, Minnesota, USA.
authors.forename: Bevan
authors.initials: B
authors.lastname: Yueh
authors.affiliation: Roswell Park Cancer Institute, Buffalo, New York, USA.
authors.forename: Anurag K
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Yao
authors.affiliation: CHUM-Hôpital Notre-Dame, Montréal, Quebec, Canada.
authors.forename: Phuc Felix
authors.initials: PF
authors.lastname: Nguyen-Tan
authors.affiliation: UCSF Medical Center, San Francisco, California, USA.
authors.forename: Sue S
authors.initials: SS
authors.lastname: Yom
authors.affiliation: Yale University, New Haven, Connecticut, USA.
authors.forename: Francis S
authors.initials: FS
authors.lastname: Cardinale
authors.affiliation: McGill University, Montréal, Quebec, Canada.
authors.forename: Khalil
authors.initials: K
authors.lastname: Sultanem
authors.affiliation: Juravinski Cancer Centre, McMaster University, Hamilton, Ontario, Canada.
authors.forename: D Ian
authors.initials: DI
authors.lastname: Hodson
authors.affiliation: University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
authors.forename: Greg A
authors.initials: GA
authors.lastname: Krempl
authors.affiliation: John H. Stroger Jr. Hospital of Cook County, Chicago, Illinois, USA.
authors.forename: Ariel
authors.initials: A
authors.lastname: Chavez
authors.affiliation: Indiana University Hospital/Melvin and Bren Simon Cancer Center, Indianapolis, Indiana, USA.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Yeh
authors.affiliation: Emory University/Winship Cancer Institute, Atlanta, Georgia, USA.
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Bruner
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000368:Aged; D004435:Eating / Q000523:psychology*; D005163:Factor Analysis, Statistical; D005260:Female; D006258:Head and Neck Neoplasms / Q000150:complications / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000523:psychology*; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires
keywords: Quality of life; factor analysis; xerostomia