title: Trajectories of fatigue in patients with breast cancer before, during, and after radiation therapy.
abstract: BACKGROUND
  Fatigue is a significant problem associated with radiation therapy (RT).
  
  
  OBJECTIVE
  This study examined how evening and morning fatigue changed from the time of simulation to 4 months after the completion of RT and investigated whether specific demographic and disease characteristics and baseline severity of symptoms predicted the initial levels of fatigue and characteristics of the trajectories of fatigue.
  
  
  METHODS
  Seventy-three women with breast cancer completed questionnaires that assessed sleep disturbance, depression, anxiety, and pain prior to the initiation of RT and the Lee Fatigue Scale, over 6 months. Descriptive statistics and hierarchical linear modeling were used for data analysis.
  
  
  RESULTS
  Large amounts of interindividual variability were found in the trajectories of fatigue. Evening fatigue at baseline was negatively influenced by having children at home and depression. The trajectory of evening fatigue was worse for women who were employed. Morning fatigue at baseline was influenced by younger age, lower body mass index, and the degree of sleep disturbance and trait anxiety. Trajectories of morning fatigue were worse for patients with a higher disease stage and more medical comorbidities.
  
  
  CONCLUSIONS
  Interindividual and diurnal variability in fatigue found in women with breast cancer is similar to that found in men with prostate cancer. However, the predictors of interindividual variability in fatigue between these 2 cohorts were different.
  
  
  CONCLUSIONS
  Diurnal variability and different predictors for morning and evening fatigue suggest different underlying mechanisms. The various predictors of fatigue need to be considered in the design of future intervention studies.
authors.affiliation: Schools of Medicine, University of California, San Francisco, California 94143-0610, USA.
authors.forename: Anand
authors.initials: A
authors.lastname: Dhruva
authors.forename: Marylin
authors.initials: M
authors.lastname: Dodd
authors.forename: Steven M
authors.initials: SM
authors.lastname: Paul
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Cooper
authors.forename: Kathryn
authors.initials: K
authors.lastname: Lee
authors.forename: Claudia
authors.initials: C
authors.lastname: West
authors.forename: Bradley E
authors.initials: BE
authors.lastname: Aouizerat
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Swift
authors.forename: William
authors.initials: W
authors.lastname: Wara
authors.forename: Christine
authors.initials: C
authors.lastname: Miaskowski
mesh_terms: D017677:Age Distribution; D000704:Analysis of Variance; D001007:Anxiety / Q000209:etiology; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications / Q000532:radiotherapy*; D002940:Circadian Rhythm; D003863:Depression / Q000209:etiology; D005221:Fatigue / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008875:Middle Aged; D015404:Nursing Methodology Research; D010146:Pain / Q000209:etiology; D011237:Predictive Value of Tests; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D012307:Risk Factors; D012495:San Francisco / Q000453:epidemiology; D012720:Severity of Illness Index; D012893:Sleep Wake Disorders / Q000209:etiology; D011795:Surveys and Questionnaires