Clinical trials are necessary for the development of improved systemic therapies for cancer. However, less than ten percent of cancer patients enroll in these studies. Taking part in a clinical trial represents a decision. This decision may be particularly difficult for cancer patients, as they are facing mortality, treatments are often associated with significant potential for morbidity, and there may be substantial uncertainty regarding risks and benefits. The primary objective of this research application is to improve patient preparation for consideration of clinical trials as a treatment option, by assessing and addressing psychosocial barriers to participation. Guided by the Cognitive-Social Health Information Processing and Ottawa Decision Support frameworks, an interactive Internet-based Preparatory Aid for Clinical Trials (PRE-ACT) will deliver tailored information to address barriers related to knowledge, goals and values, and beliefs and expectancies before the initial physician visit. The specific aims are 1) to develop and pilot test three PRE-ACT components: assessment of individual patient psychosocial barriers to clinical trial participation by Internet-based survey, automated feedback of barriers and preference clarification, and provision of individually-tailored informational video clips to address barriers; 2) to conduct a randomized clinical trial in approximately 1500 cancer patients to compare PRE-ACT vs. control condition in improving preparation to consider clinical trials; 3) to investigate relevant background and psychosocial variables associated with preparation, barriers, and treatment decision outcomes; 4) to investigate the impact of PRE-ACT on decisional conflict, satisfaction with information and discussion about clinical trials, satisfaction with treatment choice, and clinical trial participation. The underlying hypothesis is that by preparing patients for a discussion about clinical trials, they will be better able to weigh risks and benefits of this treatment option, deal with uncertainty regarding outcomes, and arrive at a treatment decision most consonant with their preferences. It is anticipated that improving decision making in this context will translate into increased patient participation in clinical trials.