Background: Investigators have to obtain informed consent before enrolling participants in clinical trials. We wanted to measure the quality of understanding among participants in clinical trials of cancer therapies, to identify correlates of increased understanding, and to assess providers' beliefs about clinical research. We also sought evidence of therapeutic misconceptions in participants and providers.
Methods: We sent a standard questionnaire to 287 adult patients with cancer who had recently enrolled in a clinical trial at one of three affiliated institutions, and surveyed the provider who obtained each patient's consent.
Findings: 207 of 287 (72%) patients responded. 90% (186) of these respondents were satisfied with the informed consent process and most considered themselves to be well informed. Nevertheless, many did not recognise non-standard treatment (74%), the potential for incremental risk from participation (63%), the unproven nature of the treatment (70%), the uncertainty of benefits to self (29%), or that trials are done mainly to benefit future patients (25%). In multivariate analysis, increased knowledge was associated with college education, speaking only English at home, use of the US National Cancer Institute consent form template, not signing the consent form at initial discussion, presence of a nurse, and careful reading of the consent form. Only 28 of 61 providers (46%) recognised that the main reason for clinical trials is benefit to future patients.
Interpretation: Misconceptions about cancer clinical trials are frequent among trial participants, and physician/investigators might share some of these misconceptions. Efforts to educate providers and participants about the underlying goals of clinical trials are needed.