Development and Validation of Measures of Patients' Perceptions Regarding Cancer Clinical Trials

Cancer clinical trials (CCTs) evaluate whether promising approaches to cancer prevention, diagnosis, and treatment are safe and effective. Progress in creating effective CT health education materials is hampered by a lack of validated instruments evaluating patients' perceptions of CCTs. The current study examined reliability and validity of newly created self-report instruments measuring patients': (1) Knowledge about CCTs (13 items); (2) Attitudes towards CCTs (20 items); (3) Self-efficacy for making a decision to participate in a CCT (9 items); (4) Receptivity to receiving information about CCTs (1 item); and (5) Intention to participate in a CCT (1 item). Participants were 83 cancer patients (64% female; mean age 64) recruited from 3 Florida medical oncology practices. Internal consistency was satisfactory in both multi-item scales using Likert response formats (Attitudes: alpha=.90; Self-efficacy: alpha=.86). Correlational analyses confirmed predictions regarding relationships among the variables assessed, thereby establishing strong validity. Patients with higher levels of knowledge had more positive attitudes towards CCTs (p<.001) and higher self-efficacy (p<.05); patients with more positive attitudes had higher self-efficacy (p<.05); patients who were more receptive to learning about CCTs had more self-efficacy (p<.01) and more positive attitudes (p= .001); finally, patients who intended to enroll in a CCT had more positive attitudes (p<.001) and were more receptive to learning about CCTs (p<.001). These results provide preliminary evidence for reliability and validity of measures of patients' perceptions of CCTs and suggest they can be used to evaluate educational interventions about CCTs.