The ctKnowledge study

Dr Siddharth Chhajlani, PhD student and medical oncology resident at Antwerp University Hospital, presented findings from the ctKnowledge study, which examines patients’ perspectives on liquid biopsies. The study enrolled approximately 195 patients across a heterogeneous cohort including neuroendocrine, gastrointestinal, and gynecological tumours. Participants were divided into two groups: those who had previously undergone liquid biopsy in a research context and those who had not. All participants completed a structured survey, and a subset also engaged in a focus group discussion.

The survey consisted of three sections. The first assessed patients’ recollection of having undergone a liquid biopsy. Notably, recall accuracy was low: only 42% of participants who had received a liquid biopsy correctly remembered the procedure, while the remainder over-reported undergoing it. Among those who accurately recalled it, the experience was generally positive, and patients clearly understood that the procedure had been performed for research rather than treatment-guiding purposes.

The second section introduced participants to the concepts of liquid biopsy and ctDNA. Only 10% of respondents had previously encountered the term ctDNA. Higher educational level correlated with better recall and understanding of the concept. Despite its complexity, most patients were able to articulate appropriate clinical applications once provided with clear, patient-friendly information, indicating that comprehension can be significantly improved through accessible explanations.

The final section addressed patient preferences regarding future use of liquid biopsies. Participants expressed a consistent preference for liquid biopsy–based monitoring if the assays could meet key performance criteria—particularly accuracy and faster turnaround time compared with conventional imaging. When presented with hypothetical scenarios comparing liquid biopsy, tissue biopsy, and CT imaging, patients generally favoured liquid biopsy when these conditions were fulfilled.

Overall, the ctKnowledge study shows that patients are receptive to liquid biopsy–based follow-up, provided that high diagnostic performance is ensured. The findings also highlight the importance of accessible, patient-centered educational materials to facilitate informed integration of liquid biopsies into routine oncology practice.