title: Explaining differences in attitude toward adjuvant chemotherapy between experienced and inexperienced breast cancer patients.
abstract: OBJECTIVE
  Previous studies have shown that patients who have experienced adjuvant chemotherapy (experienced patients) have a more favorable attitude towards chemotherapy than those who have not (inexperienced patients). However, not much is known about the reasons underlying this difference. According to the Theory of Planned Behavior, the attitude towards a particular behavior (eg, accepting chemotherapy) is based on beliefs about the likelihood of outcomes of the behavior and the evaluations of these outcomes. We used this theory to explore in what way the beliefs of experienced patients differed from those of inexperienced patients.
  
  
  METHODS
  A cross-sectional survey was undertaken among 719 patients who had been treated for early-stage breast cancer between 1998 and 2003. Patients were asked, first, to indicate the likelihood of six positive and six negative outcomes of undergoing chemotherapy and, second, to give their evaluation of these outcomes.
  
  
  RESULTS
  Four hundred forty-six women filled in the questionnaire (response rate, 62%). As hypothesized, experienced patients (ie, patients who had been treated with adjuvant chemotherapy as part of their primary treatment plan) had a more positive attitude towards chemotherapy. Experienced patients provided higher likelihood estimates of treatment advantages, such as life prolongation. In addition, they evaluated the positive outcomes of chemotherapy more favorably. With regard to the negative outcomes of chemotherapy, few differences were observed between treatment groups.
  
  
  CONCLUSIONS
  Experienced patients have more confidence in the positive outcomes of chemotherapy than inexperienced patients. This might be the result of a cognitive mechanism to justify the way in which patients were treated.
authors.affiliation: Department of Medical Decision Making, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands. s.jansen@otb.tudelft.nl
authors.forename: S J T
authors.initials: SJ
authors.lastname: Jansen
authors.forename: W
authors.initials: W
authors.lastname: Otten
authors.forename: M C M
authors.initials: MC
authors.lastname: Baas-Thijssen
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: J W R
authors.initials: JW
authors.lastname: Nortier
authors.forename: A M
authors.initials: AM
authors.lastname: Stiggelbout
mesh_terms: D000222:Adaptation, Physiological; D000223:Adaptation, Psychological; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology* / Q000601:surgery; D017024:Chemotherapy, Adjuvant / Q000523:psychology; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000523:psychology*; D009367:Neoplasm Staging; D011336:Probability; D016016:Proportional Hazards Models; D011788:Quality of Life; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires