19670 Background: Subjects who enroll in phase I cancer trials generally are those with advanced and terminal disease. Although all such patients (pts) undergo an informed consent process, there is evidence that these pts may not appreciate the primary aims of a phase I trial and have unrealistic expectations of therapeutic benefit. However, these perceptions of benefit have not been described in pts after trial enrollment. Methods: As a pilot study, pts previously enrolled on Phase I trials were interviewed regarding their retrospective perceptions of benefit. A total of 9 pts have been interviewed to date: median age: 72 yr (range: 59–82 yr); 55% male; 77% Caucasian. The interview included open-ended questions assessing patient experiences with the trial, including reasons for enrollment, impressions of quality of life, costs incurred, and other benefits. Pts’ qualitative responses were recorded and analyzed for content and themes. Results: Reasons for enrollment included hope, prior treatment failure, altruism, and family influence. Described perceptions of anticipated benefit included stabilization of disease and close monitoring of their disease. Unexpected costs involved time spent during clinic visits, financial costs, time taken off work by family members, time spent away from family, and additional trial procedures. Issues of quality of life revolved around side effects from the investigational agent. Many interviewed pts (44%) described improved quality of life off the trial as compared to during trial participation. The majority of interviewed pts (67%) believed that the trial had no effect on their survival. Conclusions: Our data suggest that pts’ perceptions of therapeutic benefit after trial enrollment may be different from pre-enrollment expectations. There would also appear to be potentially significant and otherwise undescribed out-of-pocket expenses incurred by subjects as a result of phase I enrollment. Further research is needed to examine how side effects, unexpected costs, and lack of improved survival contribute to these pts’ perceptions of trial benefit. No significant financial relationships to disclose.