Background: Breast cancer patients tend to experience numerous psychological symptoms that co-occur and form clusters. It has been proposed that a common psychological mechanism may underlie the membership of symptoms in a given cluster, but this hypothesis has never been investigated. Maladaptive emotion regulation (ER) is one possible common mechanism. Objectives: This study examined the cross-sectional and prospective relationships between subjective (experiential avoidance, expressive suppression and cognitive reappraisal) and objective measures (high frequency heart rate variability [HF HRV]) of ER and clusters of psychological symptoms including anxiety, depression, fear of cancer recurrence, insomnia, fatigue, pain, and cognitive impairments among women receiving radiation therapy for breast cancer. Method: 81 women completed a battery of self-report scales before (T1) and after (T2) radiotherapy. Resting HF-HRV was measured at T1. Results: Latent profile analyses identified between two and three clusters of patients with similar levels of symptoms across time points and between T1 and T2. Discriminant analyses showed that a higher levels of avoidance and suppression predicted membership in symptom clusters that included more severe symptoms cross-sectionally at T1 and at T2 (both ps < .0001). However, ER at T1 did not significantly predicted membership in cluster of symptoms changes between T1 and T2 (p=.15). Conclusions: Maladaptive ER strategies, more particularly avoidance, are a possible psychological mechanism underlying clusters of cancer-related psychological symptoms.

14 / IS EMOTION REGULATION A COMMON MECHANISM UNDERLYING CLUSTERS OF PSYCHOLOGICAL SYMPTOMS IN BREAST CANCER PATIENTS?​

14 / IS EMOTION REGULATION A COMMON MECHANISM UNDERLYING CLUSTERS OF PSYCHOLOGICAL SYMPTOMS IN BREAST CANCER PATIENTS?