Background: Depression in cancer patients predicts lower survival, and early identification of individuals at highest risk for depression is needed. In the general population, depression is higher in contexts of both childhood adversity and chronic interpersonal stress, but their collective influence on depressive outcomes in the first year after breast cancer diagnosis is unknown. Genetic polymorphisms related to socioemotional functioning (e.g., the serotonin transporter) may moderate the associations among childhood adversity, chronic interpersonal stress, and depressive outcomes, specifying which women are most at risk.

Methods: 460 women with invasive breast cancer were assessed for depressive symptoms and major depressive episodes (MDEs) seven times across one year. Associations between depressive symptoms and childhood adversity, chronic interpersonal stress, and the 5-HTTLPR polymorphism were examined. We used multilevel modeling for predicting longitudinal depressive symptoms, logistic regression for predicting any MDEs over the year, and multinomial logistic regression for predicting odds of belonging to Low/Recovery/High depressive symptom trajectory classes (Stanton et al., 2015). Models controlled for known sociodemographic and clinical confounding variables such as age, ethnicity, SES, cancer stage, treatments received, medical comorbidities, history of depression, and neuroticism.

Results: Higher chronic interpersonal stress predicted greater depressive symptoms at study entry (b=4.56, 95% CI [2.60,6.52]), greater odds for belonging to a High vs. Low depressive trajectory class (OR=3.16, [1.53, 6.51]), and greater odds of having an MDE (OR=2.28, [1.10, 4.73]). 5-HTTLPR moderated the influence of chronic interpersonal stress on depressive symptoms over time (b=0.24, [0.06,0.41]), with no decline in symptoms for SS genotype women under high chronic interpersonal stress vs. significant improvement in symptoms despite high chronic interpersonal stress for LL/LS genotype women. There were no significant effects of childhood adversity on depressive outcomes considered.

Conclusion: Women with greater chronic interpersonal stress are at risk for high, unremitting depressive symptom trajectories and MDEs in the first year after invasive breast cancer diagnosis. Unchanged depressive symptoms across the year were most pronounced for women bearing the SS allele of the 5-HTTLPR polymorphism. Women with high chronic interpersonal stress and the SS genotype may benefit from early intervention to prevent depression after breast cancer diagnosis.

Citation Format: Jacqueline HJ Kim, Steve W Cole, Karen L Weihs, Annette L Stanton. Chronic interpersonal stress predicts depressive outcomes in the first year of invasive breast cancer: Moderation by the serotonin-transporter polymorphism [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD12-02.