title: Minimal clinically important differences in the Edmonton symptom assessment system in patients with advanced cancer.
abstract: BACKGROUND
  Longitudinal symptom monitoring is important in the setting of patients with advanced cancer. Scores over time may naturally fluctuate, although a patient may feel the same.
  
  
  OBJECTIVE
  The purpose of this study was to determine the minimal levels of change required to be clinically relevant (minimal clinically important difference [MCID]) using the Edmonton Symptom Assessment System (ESAS).
  
  
  METHODS
  Between 1999 and 2009, patients completed the ESAS before palliative radiotherapy and at follow-up. MCIDs were calculated using both the anchor- and distribution-based methods for improvement and deterioration; 95% confidence intervals for the differences in mean change scores between adjacent categories also were calculated.
  
  
  RESULTS
  A total of 276 patients completed the ESAS at baseline and during at least one follow-up visit. At the four-week follow-up, decrease of 1.2 and 1.1 units in pain and depression scales, respectively, constituted clinically relevant improvement, whereas increase of at least 1.4, 1.8, 1.1, 1.1, and 1.4 units, respectively, in pain, tiredness, depression, anxiety, and appetite loss items were required for deterioration. At the subsequent follow-ups, these values were similar. Overall, the MCID for improvement tended to be smaller than that for deterioration. The distribution-based method estimates tended to be larger than the 0.3 SD estimates, but closer to the 0.5 SD estimates.
  
  
  CONCLUSIONS
  MCIDs allow health care professionals to determine the success of treatment in improving the patient's quality of life. MCIDs may prompt health care professionals to intervene with new treatment. Future studies should confirm our findings with a variety of anchors.
authors.affiliation: Rapid Response Radiotherapy Program, Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Gillian
authors.initials: G
authors.lastname: Bedard
authors.forename: Liang
authors.initials: L
authors.lastname: Zeng
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.forename: Natalie
authors.initials: N
authors.lastname: Lauzon
authors.forename: Lori
authors.initials: L
authors.lastname: Holden
authors.forename: May
authors.initials: M
authors.lastname: Tsao
authors.forename: Cyril
authors.initials: C
authors.lastname: Danjoux
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barnes
authors.forename: Arjun
authors.initials: A
authors.lastname: Sahgal
authors.forename: Michael
authors.initials: M
authors.lastname: Poon
authors.forename: Edward
authors.initials: E
authors.lastname: Chow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000175:diagnosis / Q000453:epidemiology; D015984:Causality; D015897:Comorbidity; D005221:Fatigue / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000532:radiotherapy*; D009864:Ontario / Q000453:epidemiology; D010146:Pain / Q000175:diagnosis / Q000453:epidemiology; D063868:Patient Outcome Assessment; D015995:Prevalence; D011788:Quality of Life; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires