Psychoneuroimmunology and the course of breast cancer: An overview the impact of psychosocial factors on progression of breast cancer through immune and endocrine mechanisms

This review focuses upon possible mediators of the frequently noted associations between psychosocial factors and the progression of breast cancer. First, host‐related endocrine and immunological processes that may play an important role in the carcinogenesis and progression of breast cancer are summarized. Second, the effects of several endocrines on different components of the immune system that have been shown to be related to the course of breast cancer are addressed. Third, studies examining the effect of psychosocial factors on immune function conducted with breast cancer patients and healthy individuals are described. Based on this review, it can be concluded that causal relations between psychosocial stressors, endocrine and immune processes, and breast cancer progression remain to be elucidated. It can be hypothesized that psychosocial stressors influence the course of breast cancer by modulating endocrine processes which are directly related to tumor growth or indirectly related by decreasing immunologic control over tumor development and metastases. Finally, methodological pitfalls that plague this line of research are summarized and recommendations for future psychoneuroimmunologic research in breast cancer are provided