Effect of patients' expectations of benefit with standard breast cancer adjuvant chemotherapy on participation in a randomized clinical trial: A clinical vignette study

Patients frequently overestimate the benefit of standard breast cancer adjuvant therapy. This is due in part to vague doctor-patient communication. To examine how the doctor's description and patient's expectations of the benefit of standard therapy affect clinical trial participation, we randomized 282 female cancer patients to one of two versions of a clinical vignette describing a choice between standard cyclophosphamide, methotrexate, and fluorouracil (5FU) (CMF) and a randomized trial comparing CMF with cyclophosphamide, doxorubicin, and 5FU (CAF). The vignettes differed only on whether results with CMF were described verbally or numerically in terms of disease-free survival (DFS). After selecting CMF or the trial, patients estimated their 10-year DFS with CMF. Patients were randomized 3:1 to the verbal vignette. The trial was selected by 110 of 210 (52.4%) verbal vignette patients versus 25 of 72 (34.7%) numeric vignette patients (P = .01). Estimates of 10-year DFS with CMF varied considerably; many were inaccurate. When patients in the verbal vignette group were divided into thirds according to DFS estimate, 22 of 64 (34.4%) in the top third selected the trial versus 38 of 64 (59.4%) and 38 of 65 (58.5%) in the middle and bottom third, respectively (P = .005). Younger age, college education, and previous participation in a trial also predicted trial selection. Multivariate logistic regression suggested that the benefit expected from CMF was more important than how benefit was described in treatment selection. Assuring realistic patient expectations of standard adjuvant therapy benefit is likely to be important during discussion of clinical trials.