Are we getting informed consent from patients with cancer?

We developed a consent form for a hypothetical trial and asked patients to underline information that was pertinent to their decision to accept or refuse to participate in the proposed trial. We also investigated whether patients correctly interpreted statements describing the probability of certain events occurring. Of the 50 patients, 74% did not indicate that both risks and benefits were pertinent. Of the 20 patients who would not enter the trial, 70% focused on risks of therapy only. In contrast, of the 30 who agreed to enter, only 33% focused entirely on risks, while 10% did not note potential for either benefit or risk. For each of four probability statements, patients chose one of four possible interpretations, only one of which was correct. Depending on the statement, between 26 and 54% of the interpretations were incorrect. It appears that many decisions regarding trial entry may be based upon incomplete or incorrect information.