Background Communication aids can facilitate advance care planning (ACP) conversations. The vignette technique involves using scenarios of sensitive clinical circumstances to explore research participants’ perspectives. Its use in ACP research remains unexplored.

Aim To examine the use of the vignette technique in ACP discussions with cancer patients and their caregivers.

Methods Secondary analysis using qualitative methods on data from three previous studies examining cancer patients’ and caregivers’ perspectives on ACP and the acceptability of a cancer specific ACP intervention. Four vignettes depicting patients in different stages of cancer assisted with ACP considerations in each stage. Data was extracted from 85 responses (42 patients; 43 caregivers) and underwent thematic analysis, informed by grounded theory methods.

Results Participants may not identify with vignettes, despite similarities in prognosis, disease burden or disease stage. Vignettes, however, may promote and support ACP considerations, conversations, and decisions when used in a facilitated context. They may also confront or be unmemorable. The vignette technique is acceptable but requires cautious, individualised, informed, and selective use in oncology.

Discussion Sensitive patient- and family-centred conversations in oncology require varied techniques to facilitate discussions. Vignettes during face-to-face discussions can aid understanding about ACP’s relevance. However, they may be more acceptable in research settings with biassed samples and allocated time rather than real-world situations.

Conclusion Patients and caregivers can be informed about varied reactions to the use of vignettes in ACP discussions, and be offered the opportunity to choose whether health professionals incorporate them into ACP discussions/interventions.