Knowledge and understanding among cancer patients consenting to participate in clinical trials.

The aim of this study was to explore the fulfilment of the requirements of informed consent in patients participating in cancer clinical trials. All patients consenting to a phase II or III clinical trial during one year were included (n=325, 176 women, 54%). Data were collected by a questionnaire, Quality of Informed Consent. The response rate was 87%. High levels of knowledge (>80%) were found for items concerning voluntariness, randomisation, benefits for future patients, participation in a research trial, and the right to withdraw. Less than 50% responded correctly to items about risks associated with the trial, the unproven nature of the trial and issues about insurances. High levels of perceived understanding were reported. Despite high levels of knowledge and perceived understanding in the majority of elements of informed consent, improvements are warranted regarding knowledge about risks, the unproven nature of the treatment and the duration of treatment.