The Importance of Disease-Free Survival as a Clinical Trial Endpoint: A Qualitative Study Among Canadian Survivors of Lung Cancer

Abstract

In lung cancer trials, overall survival is a well-validated and widely used endpoint; yet, in the context of adjuvant or curative intent treatments, disease-free survival (DFS) may be a better indicator of transformative patient outcomes. Although use of DFS is growing, patient perceptions of its relevance have not been established. We aimed to understand the importance of DFS as a trial endpoint, from the perspective of survivors of lung cancer. Web-based qualitative interviews were conducted with Canadian survivors of stage Ib–IIIa lung cancer. Participants described their experiences of cancer diagnosis and treatment, including their treatment goals and priorities. Participants then provided their perspectives on DFS and overall survival, and how well each aligned with their treatment priorities. Thematic analysis was used to explore patterns in responses. Among the 18 participants (mean age, 64 years), 83% were female, most (89%) had received surgery, and 56% received chemotherapy. Most participants viewed DFS as an intrinsically meaningful treatment outcome, for reasons such as alignment with treatment goals, and the perception that DFS would help maintain a high quality of life. One individual was interested in DFS only as a potential surrogate for overall survival. Participants desired access to new treatments that improve DFS and emphasized this within the context of promoting patient agency in treatment decision making. These findings suggest DFS is a meaningful endpoint from the perspective of survivors of lung cancer; and may help inform decisions regarding regulatory approval and reimbursement of new treatments based on DFS data.