Understanding of an aggregate probability statement by patients who are offered participation in Phase I clinical trials

Abstract

BACKGROUNDThere is concern that patients with poor numeracy may have difficulty understanding the information necessary to make informed treatment decisions. The authors sought to characterize a special form of numeracy among patients with advanced cancer who were offered participation in Phase I oncology clinical trials.METHODSSurveys were administered to 328 cancer patients who were considering Phase I trials. Their frequency‐type numeracy was assessed using a multiple‐choice question involving a hypothetical scenario in which a physician stated that an experimental treatment would control cancer in “40% of cases like yours.” In univariate and multivariable analyses, patient characteristics that were associated with better numeracy were identified.RESULTSThe correct frequency‐type interpretation was selected by 72% of respondents. Fourteen percent of respondents incorrectly selected a belief‐type answer, “The doctor is 40% confident that the treatment will control my cancer.” In a multivariable model, patients who answered incorrectly tended to have less formal education and less experience with experimental therapies.CONCLUSIONSBecause the misunderstandings some patients demonstrated may influence their treatment decision making adversely, it is critical to identify such patients and to give them special consideration when communicating information about potential risks and benefits of treatment. Cancer 2004. © 2004 American Cancer Society.

Communication and informed consent in phase 1 trials: a review of the literature

“…Patient misconception can only be identified if both investigator and patient communicate expectations of benefit and risk in frequency-type terms; future research in this area should take this into consideration, and investigators should ensure that there is consistency in the probabilitytype expressions they use with their patients. Research shows that education is associated with the understanding of probability-type statements [30]; hence, it is important that investigators identify patients who are more likely to misinterpret probability statements, and develop alternative strategies to communicate treatment-outcome information. Ultimately, whether the cause of over-expectation of benefit and risk is investigator-or patient-centred, or a result of the methodology employed, the responsibility to address the issue and ensure patients are adequately informed rests with the investigator, and appropriate training in this area needs to be sought.…”

Research Participants' High Expectations of Benefit in Early-Phase Oncology Trials: Are We Asking the Right Question?

“…We measured participants' aptitude for numbers by using the Subjective Numeracy Scale 16 and a single item querying understanding of a statement of aggregate probability. 17 We used the Quality of Informed Consent 18 measure to assess understanding of the elements of informed consent in clinical research. We used the Life Orientation Test-Revised 19 to measure participants' dispositional optimism, a personality trait defined in terms of having general expectations of positive outcomes in one's future.…”

Communication and informed consent in phase 1 trials: a review of the literature from January 2005 to July 2009

“…Four studies employed structured or semi-structured interview techniques to elicit patients' understanding of P1 trials and one used interviews to determine whether expectations of benefit would differ depending on the type of question employed by the interviewer [5,[9][10][11]. The remaining studies used questionnaires or surveys to examine motivations for participation in P1 trials, decisional conflict, numeracy, need for palliative care and interventions to help patients' understanding [12][13][14][15][16][17].…”