Efficacy of a Brief Ecologically Boosted Emotion Regulation Group Intervention on Cancer‐Related Fatigue in Breast Cancer Survivors: A Randomized Controlled Trial

Background Cancer‐related fatigue (CRF) is one of the most frequently reported symptoms among breast cancer survivors. Recommendations regarding nonpharmacological treatments for CRF include physical activity, psychosocial, and mind–body interventions. Despite the close association of CRF with psychological symptoms, to our knowledge, no study has assessed the impact of a psychosocial intervention on CRF among patients meeting criteria for clinical levels of psychological symptoms. Aim This study presents findings on changes in CRF, sleep disturbances, energy levels, and physical activity from a randomized controlled trial (RCT) evaluating the efficacy of an eight‐session emotion and self‐regulation group intervention ecologically boosted through daily app‐based prompts. The intervention, specifically designed for breast cancer survivors in the early survivorship period who exhibited clinical levels of psychological symptoms, showed its efficacy in targeting some psychological symptoms (i.e., worry, intrusive thoughts, and negative emotions). Method At the end of radiation therapy treatment, breast cancer survivors were screened for clinical levels of psychological symptoms and randomly assigned to either an immediate ( n = 61) or a delayed intervention group ( n = 59, intervention delayed by 5 months). CRF, sleep disturbances, energy levels, and physical activity were assessed using self‐reported questionnaires, visual analog scales, and ecological momentary assessments. Assessments were performed at baseline (T1), 5 months (T2), and 10 months (T3). Mixed models were conducted to evaluate the intervention’s efficacy in treating CRF. Results Treated patients reported less general fatigue ( p = 0.028), reduced motivation ( p = 0.005), and mental fatigue ( p = 0.024), as well as lower levels of habitual physical fatigue ( p = 0.043) and momentary fatigue in daily life ( p = 0.009). Conclusions Our study highlights the usefulness of targeting emotion and self‐regulation in a brief group intervention to treat CRF among patients with clinical levels of psychological symptoms. Further research is needed to clarify the mechanisms driving the efficacy of the intervention.