title: An international prospective study establishing minimal clinically important differences in the EORTC QLQ-BM22 and QLQ-C30 in cancer patients with bone metastases.
abstract: OBJECTIVE
  Quality of life (QOL) is frequently an endpoint in clinical trials involving patients with advanced cancer. Statistical significance of minimal differences can be achieved with sufficient sample size, yet the actual clinical relevance is unknown. The purpose of this study was to establish the minimal clinically important difference (MCID) for the European Organisation for Research and Treatment of Cancer (EORTC) bone metastases module (EORTC QLQ-BM22).
  
  
  METHODS
  Patients with bone metastases across seven countries were prospectively enrolled in a trial validating the EORTC QLQ-BM22 and completed the QLQ-BM22 and core measure (QLQ-C30) at baseline and 1-month follow-up. MCIDs were calculated for each QOL scale for both improvement and deterioration using both an anchor- (performance status) and distribution-based approach.
  
  
  RESULTS
  A total of 93 patients completed both baseline and follow-up QOL and had recorded performance status at both intervals. Statistically significant meaningful differences were seen in seven scales. There were improvements of 30.5 (95 % confidence interval, 9.0 to 52.0), 20.1 (7.1 to 33.2), 30.5 (13.8 to 47.3) and 19.6 (5.0 to 34.3) in the pain, painful site, painful characteristic and functional interference scales, respectively, demonstrated clinical relevance. Decreases of 12.4 (0.3 to 24.6), 22.4 (11.8 to 32.9) and 13.5 (1.9 to 25.1) were required to represent clinically relevant deterioration in emotional functioning, global health status and financial issues, respectively. Minimal differences for improvement were closest to 0.5 standard deviations (SD) while for deterioration, closer to 0.3 SD on the QLQ-BM22.
  
  
  CONCLUSIONS
  Identification of requirements for clinical significance can assist in determining the relevance of QOL changes after treatment and in sample size determination in future trials. Our study is limited by the small sample size. Future studies should continue to determine MCID and confirm our findings using a variety of appropriate anchors and in a larger sample.
authors.affiliation: Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario, Canada M4N 3M5.
authors.forename: Liang
authors.initials: L
authors.lastname: Zeng
authors.forename: Edward
authors.initials: E
authors.lastname: Chow
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.forename: Ling-Ming
authors.initials: LM
authors.lastname: Tseng
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Hou
authors.forename: Alysa
authors.initials: A
authors.lastname: Fairchild
authors.forename: Vassilios
authors.initials: V
authors.lastname: Vassiliou
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Jesus-Garcia
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Alm El-Din
authors.forename: Aswin
authors.initials: A
authors.lastname: Kumar
authors.forename: Fabien
authors.initials: F
authors.lastname: Forges
authors.forename: Wei-Chu
authors.initials: WC
authors.lastname: Chie
authors.forename: Gillian
authors.initials: G
authors.lastname: Bedard
authors.forename: Andrew
authors.initials: A
authors.lastname: Bottomley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000150:complications / Q000523:psychology* / Q000556:secondary; D005221:Fatigue / Q000209:etiology; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D010146:Pain / Q000209:etiology; D011446:Prospective Studies; D011594:Psychometrics / Q000295:instrumentation; D011788:Quality of Life; D011795:Surveys and Questionnaires