UC Irvine

The presented doctoral work explores the relationship between psychosocial stress in the form of life events (LEs) and breast cancer risk. Life event valence and perception of life event stress were examined in an attempt to better quantify the effects of life events on breast cancer risk. Antidepressant medication use following LEs was used to estimate perturbations in stress physiology resulting from LEs. The population studied comprises 664 population-based incident, invasive primary breast cancer cases, 203 population-based controls and 156 sister controls that were part of the Hereditary Breast and Ovarian Cancer (HBOC) study of the University of California, Irvine (CA58860). A case-control design was utilized to examine the distribution of life events among cases and controls. Unconditional and conditional logistic regression was used to calculate ORs and 95% CIs for breast cancer risk estimation associated with LEs. This investigation identified stressful, negative valence later life events as important risk factors in future breast cancer risk. Pervious personal illness specifically stood out as a breast cancer risk factor. Early life exposures and genetics seem to influence susceptibility to the effects of later life events on breast cancer risk. Antidepressant medication could possibly attenuate the effects of life event stress on breast cancer risk. This research provides insight into the complex psycho-neuro-immunological interactions at play contributing to breast cancer onset. A more fine-tuned quantification of stress perception and physiological alterations are recommended. Future research is needed to explore the effects of major life stressors on breast cancer risk according to molecular subtype.