A phase I clinical trial was started in order to determine the recommended doses of capecitabine and epirubicin, when administered in combination with a fixed dose of cyclophosphamide (600 mg/m(2) day 1 q3 weeks) in patients with inoperable or recurrent breast cancer. This study consists of five dose levels with combinations of three levels of epirubicin (75, 90 and 100 mg/m(2) day 1 q3 weeks) and three levels of capecitabine (1255, 1657 and 1800 mg/m(2)/day consecutive administration for 2 weeks followed by 1 week of rest). Dose escalation and de-escalation decisions are based on a continual reassessment method (CRM). We conducted a survey of the clinical oncologists participating in this trial to determine the dose escalation/de-escalation rule, including a prior distribution for model parameters used in the CRM.