title: Is it best to expect the worst? Influence of patients' side-effect expectations on endocrine treatment outcome in a 2-year prospective clinical cohort study.
abstract: This study aims to determine the role of patient expectations as potentially modifiable factor of side-effects, quality of life, and adherence to endocrine treatment of breast cancer.
  
  
  
  A 2-year prospective clinical cohort study was conducted in routine primary care with postoperative patients with hormone-receptor-positive breast cancer, scheduled to start adjuvant endocrine treatment. Structured patient-reported assessments of side-effects, side-effect expectations, quality of life, and adherence took place during the first week post-surgery and after 3 and 24 months of endocrine treatment.
  
  
  
  Of 111 enrolled patients, at 3 and 24 months, 107 and 88 patients, respectively, were assessed. After 2 years of endocrine treatment, patients reported high rates of side-effects (arthralgia: 71.3%, weight gain: 53.4%, hot flashes: 46.5%), including symptoms not directly attributable to the medication (breathing problems: 28.1%, dizziness: 25.6%). Pre-treatment expectations significantly predicted patient-reported long-term side-effects and quality of life in multivariate models controlling for relevant medical and psychological variables. Relative risk of side-effects after 2 years of endocrine treatment was higher in patients with high negative expectations at baseline than in those with low negative expectations (RR = 1.833, CI 95%, 1.032-3.256). A significant interaction confirmed this expectation effect to be particularly evident in patients with high side-effects at 3 months. Furthermore, baseline expectations were associated with adherence at 24 months (r = -0.25, P = 0.006).
  
  
  
  Expectations are a genuine factor of clinical outcome from endocrine treatment for breast cancer. Negative expectations increase the risk of treatment-specific side-effects, nocebo side-effects, and non-adherence. Yet, controlled studies are needed to analyze potential causal relationships. Optimizing individual expectations might be a promising strategy to improve side-effect burden, quality of life, and adherence during longer-term drug intake.
  
  
  
  ClinicalTrials.gov Identifier: NCT02088710.
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg y.nestoriuc@uke.de.
authors.forename: Y
authors.initials: Y
authors.lastname: Nestoriuc
authors.affiliation: Department of Clinical Psychology and Psychotherapy, Philipps-University of Marburg, Marburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: von Blanckenburg
authors.affiliation: Department of Clinical Psychology and Psychotherapy, Philipps-University of Marburg, Marburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schuricht
authors.affiliation: Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Barsky
authors.affiliation: Department of Gynecology and Obstetrics, Krankenhaus Nordwest, Frankfurt/Main, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Hadji
authors.affiliation: Department of Gynecology and Obstetrics, Krankenhaus Nordwest, Frankfurt/Main, Germany.
authors.forename: U-S
authors.initials: US
authors.lastname: Albert
authors.affiliation: Department of Clinical Psychology and Psychotherapy, Philipps-University of Marburg, Marburg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Rief
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D047072:Aromatase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D015331:Cohort Studies; D064420:Drug-Related Side Effects and Adverse Reactions / Q000145:classification / Q000473:pathology; D047628:Estrogen Receptor alpha / Q000235:genetics; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D011182:Postoperative Care; D011788:Quality of Life; D013629:Tamoxifen / Q000008:administration & dosage* / Q000009:adverse effects; D016896:Treatment Outcome
chemical_list: D047072:Aromatase Inhibitors; D047628:Estrogen Receptor alpha; D013629:Tamoxifen
keywords: adherence; adverse effects; expectation; nocebo effect; psycho-oncology; quality of life