Predictors of patient-reported toxicities from endocrine therapy: Importance of illness perceptions, treatment beliefs, and fear of recurrence.

542 Background: Numerous studies have documented the toxicities of endocrine therapy (ET) for early breast cancer (EBC) and their deleterious impact on quality of life and adherence. However, little is known about the factors that underlie patient's susceptibility to report toxicities. The identification of risk factors for toxicities from ET is important as it would allow early targeting of symptom management interventions for women more vulnerable to adverse effects of ET. This prospective study aims to examine the impact of pre-treatment perceptions of EBC, ET beliefs and fear of breast cancer (BC) recurrence (FBCR) on toxicities reported after 6 months of ET. Methods: Women diagnosed with EBC completed a survey prior to initiating endocrine therapy, then at 3, 6 and 12 months. Standardized self-report instruments were used to assess EBC perceptions, ET beliefs, FBCR and toxicities. Clinical and treatment variables were also evaluated. Univariate analyses and mulitivariate regression were conducted to ...