Factors affecting enrollment in randomized controlled trials conducted for patients with metastatic breast cancer

Background It is critical to obtain informed consent from eligible patients to complete clinical trials. We investigated the factors that affect the participation rates of eligible patients. Patients and methods Patients with metastatic breast cancer who were eligible for SELECT BC or SELECT BC-CONFIRM trials, randomized controlled trials conducted for patients with chemotherapy-naive metastatic breast cancer were recruited to prospective studies, SELECT BC-FEEL and SELECT BC-FEEL II, respectively. SELECT BC FEEL and SELECT BC-FEEL II were conducted to identify the factors affecting the rates at which informed consent was obtained, using a self-administered questionnaire we developed. Results In total, 232 patients participated in the studies. The patients who agreed to take part in the randomized trials were more likely than the refusers to answer that they decided to participate because: ‘My doctor wanted me to participate in this trial’ (P = 0.00000), ‘ My family or friends wanted me to participate in this trial’ (P = 0.00000), ‘Both treatment regimens used in the trial are suitable to me’ (P = 0.00383), ‘I know that the trial is conducted to determine which is a better treatment’ (P = 0.01196), and ‘ I think that my participation in the trial will contribute to the benefit to future patients with the same disease’ (P = 0.00756). Conclusions To enhance the consent rate in randomized trials of metastatic breast cancer patients, concepts of the trials must be considered important and acceptable not only by patients but also by doctors and their families.