Breast cancer is a traumatic experience. Those diagnosed with breast cancer often experience psychological symptoms such as depression, anxiety, and stress. However, traumatic experiences do not only cause psychological symptoms, but also can lead to positive changes named as posttraumatic growth (PTG). In the present study, it was aimed to examine both the psychological symptom (depression, anxiety, stress) and PTG levels of women with breast cancer and the relationship of these variables with core beliefs challenge and rumination types. Sociodemographic and Cancer-Related Information Form, Depression Anxiety Stress Scale-21, Posttraumatic Growth Inventory, Core Beliefs Inventory, and Event-Related Rumination Inventory were applied to 201 women with breast cancer diagnosis (Mage = 47.81, SD = 8.58), mediation relations of variables were examined with Process Macro. As a result of the analysis, it was determined that the psychological symptom levels of the majority of the participants were low and their PTG levels were above medium. It was determined that core beliefs challenge positively predicted depression, anxiety, stress, and PTG. Intrusive rumination mediated the relationship between core beliefs challenge and depression, anxiety and stress; deliberate rumination mediated the relationship between core beliefs challenge and PTG. In other words, as the core belief challenge of the participants increase, both psychological symptom and PTG levels increase. In addition, those who use intrusive rumination experience more psychological symptom, and those who use deliberate rumination experience more PTG. The present study reveals the importance of cognitive processes in understanding the psychological symptoms and PTG in women with breast cancer. Keywords: Breast cancer, psychological symptom, posttraumatic growth, core belief challenge, event-related rumination
18 - SOCIAL SUPPORT AS A MODERATOR IN THE RELATIONSHIP BETWEEN INTRUSIVE THOUGHTS AND PSYCHOLOGICAL SYMPTOMS AMONG SPANISH-SPEAKING LATINAS WITH BREAST CANCER