Introduction We are developing a core outcome set (COS) for palliative cancer care research into prognostication (prediction of survival). Studies in this field often measure a variety of clinical and service-level outcomes, but do not routinely measure outcomes that are important to patients and carers. The experiences of these stakeholders are essential for producing a meaningful COS.

Aims To identify and synthesise qualitative data on patients’ and carers’ experiences of prognostication in palliative cancer care.

Methods We searched five electronic databases (MEDLINE, Embase, CINAHL, PsycINFO, and the Cochrane Library) from inception up to March 2022. The search included qualitative or mixed methods studies exploring how adult cancer patients and/or carers are affected by prognostication. Data describing outcomes and experiences of prognostication were extracted and thematically synthesised, using the Core Outcome Measures in Effectiveness Trials (COMET) taxonomy as a framework to develop themes.

Results From 8,075 results, we identified 9 papers describing patients’ and carers’ experiences of prognostication. We identified 28 themes from these papers and organised these into eight domains within the COMET taxonomy: 1) psychiatric outcomes; 2) spiritual, religious, and/or existential functioning/wellbeing; 3) emotional functioning/wellbeing; 4) social functioning; 5) global quality of life; 6) delivery of care; 7) perceived health status; 8) personal circumstances. The main themes identified were: avoidance/denial, maintaining hope, preparedness for end-of-life, and treatment preferences.

Conclusions We have identified 28 themes as potential candidates for inclusion in the future COS. The next stage of the study will investigate stakeholders’ perspectives on these themes and other potentially suitable items for inclusion, identified through linked reviews.

Impact Standardising outcome reporting through a COS will improve the comparability of future prognostic research, and match better with patient and carer experiences. This will lead to better evidence synthesis, clinical practice, and ultimately improve access to support for those living with terminal cancer when receiving a prognosis.