Capturing the Complexity of Cancer-Related Symptom Burden: Mental Health and Pain Dynamics in Breast Cancer Survivors Using Snapshot and Ecological Momentary Assessment

Purpose: Mental health symptoms frequently persist following treatment for breast cancer. However, traditional cross-sectional single-timepoint assessments overlook how symptoms fluctuate in daily life. This study integrated single-timepoint clinical measurements with ecological momentary assessment (EMA) to characterise the multidimensional and dynamic nature of mental health symptoms in breast cancer survivors versus non-cancer controls.Methods: Thirty breast cancer survivors (6-36 months post-chemotherapy) and 19 non-cancer controls completed self-report questionnaires tapping into a range of mental health symptoms. Total scores and the proportion meeting the clinical threshold scores were calculated. Additionally, participants completed daily EMA sessions using the Mindtrax app assessing affective, cognitive, and somatic mental health dimensions. Intraindividual symptom severity and variability for each dimension were calculated and Spearman rank correlations were used to examine relationships between dimensions. Results: For single-timepoint questionnaires, a higher proportion of breast cancer survivors, compared to controls, met clinical thresholds across multiple domains and demonstrated significantly elevated symptom severity for depression, anxiety, perceived cognitive impairment, fatigue, and sleep disturbance, as well as compromised quality of life. For EMA, survivors exhibited significantly higher intraindividual daily somatic symptom severity compared to controls, driven by pain intensity. Within the breast cancer survivor group, we observed moderate-to-strong positive correlations between daily affective, cognitive, and somatic symptom severity, revealing substantial symptom co-occurrence. Conclusions: Integrating single-timepoint and EMA reveals that breast cancer survivors experience persistent, multidimensional symptom burden extending well beyond treatment completion. Implications for Cancer Survivors: Our findings advocate for extended survivorship monitoring and accessible, transdiagnostic care approaches that address symptom clustering and real-world functional impact.