Existential distress in patients with advanced cancer and their caregivers: study protocol of a longitudinal cohort study

INTRODUCTION: At the end of life, patients with advanced cancer and their informal caregivers may confront multiple existential concerns. Despite the strong potential to alleviate existential distress through psychosocial interventions, existential distress and its impact on healthcare outcomes have not yet been studied systematically. We aim to investigate the frequency, longitudinal trajectory and predictive impact of existential distress on end-of-life outcomes. We further aim to determine patients’ and caregivers’ specific need for and utilisation of psychosocial support for existential distress. METHODS: This longitudinal cohort study will consecutively recruit 500 patients with advanced cancer and 500 caregivers from oncological outpatient and inpatient clinics. Participants will complete self-report questionnaires (sociodemographic and disease-related characteristics, existential distress, end-of-life outcomes, resources and support needs) at five points of assessment (at baseline and after 3, 6, 9 and 12 months). At baseline and 6-month follow-up, we will conduct structured diagnostic interviews to assess mental disorders. Statistical analyses will include descriptive statistics to determine the prevalence of existential distress, mental disorders and end-of-life outcomes; multiple linear and logistic regression analyses to calculate the predictive impact of existential distress on end-of-life outcomes; and growth mixture models to analyse longitudinal trajectories of existential distress. DISCUSSION: This study will provide comprehensive knowledge about patients’ and caregivers’ existential concerns. The longitudinal empirical data will allow for conclusions concerning the frequency and course of existential distress throughout 1 year. This important extension of existing cross-sectional research will contribute to further develop targeted psychosocial interventions. Profiles of existential distress may be applied by clinicians from multiple professions and help to address existential concerns effectively. ETHICS AND DISSEMINATION: The study was approved by the institutional research ethics committee (reference number LPEK-0177). Results will be presented at scientific conferences and published in peer-reviewed journals. Other forms of dissemination will include sharing results on the psychometric properties of the structured demoralisation interview with international research groups and communication with healthcare professionals providing psychosocial treatment for patients and caregivers. Following scientific standards, our progress will be regularly updated on ClinicalTrials.gov. TRIAL REGISTRATION NUMBER: NCT04600206.