Levels of knowledge and perceived understanding among participants in cancer clinical trials - factors related to the informed consent procedure.

BACKGROUND: An informed consent from patients participating in cancer clinical trials is mandatory according to international and national guidelines and laws. Insufficient knowledge and understanding by trial participants have been reported in several studies. PURPOSE: The aims of this study were to investigate factors of importance for knowledge and understanding about cancer clinical trials among trial participants. METHODS: All patients consenting to a phase II or III clinical trial during 1 year were invited (n = 325). Data on knowledge and perceived understanding were collected by a questionnaire, Quality of Informed Consent. RESULTS: are based on data from 268 patients (82%). Associations between knowledge and perceived understanding as well as clinical, socio-economic factors, and factors related to the informed consent procedure were tested. Results In the multivariate analysis no statistically significant associations were found between knowledge and any of the factors. Patients who reported longer time for trial information before their decision to participate, those who found the decision easy to take, and patients who reported use of other information sources had statistically significant higher perceived understanding. No differences in mean scores for knowledge or perceived understanding were found for any of the clinical factors (age, gender, diagnostic group, trial phase), socio-economic factors (education, marital status), and the following factors related to the informed consent procedure; presence of relative or nurse at information about the trial or previous participation in clinical trials. LIMITATIONS: No study specific questions were included due to the number of trials (n = 35). CONCLUSION: Strategies to increase patients' knowledge needs to be elaborated in order to improve the fulfilment of the requirements of informed consent in participants in cancer clinical trials.