Longitudinal Mediating Role of Cancer‐Coping Self‐Efficacy Between Symptom Occurrence and Quality of Life Among Cancer Patients: A Cross‐Lagged Panel Model

ABSTRACT Purpose Although the positive correlation between self‐efficacy and quality of life and the negative correlation between symptom occurrence and self‐efficacy are well established in the cancer literature, the underlying mechanism, whether self‐efficacy mediates the effect of symptoms on quality of life, remains unclear due to the cross‐sectional design of prior studies. Longitudinal investigation is crucial for establishing the causal mechanism of self‐efficacy in mitigating the adverse impact of cancer‐related symptoms on quality of life. Aim To examine the longitudinal mediating effect of self‐efficacy on the relationship between symptom occurrence and quality of life among 534 cancer patients on treatment with moderate to high symptoms. Methods This is a secondary data analysis of the longitudinal mediating effect. A sample of patients with moderate to high symptoms on cancer treatments ( N = 534) from a randomised controlled trial was used. We adopted a cross‐lagged panel model (CLPM) approach to test the longitudinal mediating effect with three waves. The longitudinal invariance of the measurement was previously tested. Results The results showed that cancer‐coping self‐efficacy predicted the following assessment of symptom occurrence, but not vice versa. Also, cancer‐coping self‐efficacy had an immediate direct impact on quality of life and the influence sustained to the following assessment. Our mediating analysis showed that cancer‐coping self‐efficacy totally mediated the relationship between symptom occurrence and quality of life (unstandardized β = −0.008, standardised B = −0.036, p = 0.036, CI 95 = [−0.001, −0.016]). Conclusion Our findings provide initial evidence supporting the causal mechanism of cancer‐coping self‐efficacy in interventions that aim for symptom management and quality of life improvement. Implications This study is the first to test the longitudinal mediating mechanism of cancer‐coping self‐efficacy in the relationship between symptom occurrence and quality of life among the cancer population. Further testing using a randomised controlled trial of a specifically designed self‐efficacy‐enhancing intervention is needed. Patient or Public Contribution No patient or public contribution.