Immune function and adjustment style: do they predict survival in breast cancer?

The aim of this study was to investigate the role of immune status and psychosocial factors in survival from early breast cancer (N=61). Baseline assessments included lymphocyte number and function, natural killer cell activity (NKA), plasma cortisol and prolactin level. Psychosocial measures included anxiety, depression and mental adjustment to cancer and social support. Length of follow-up was 6.1-7.9 years with 14 (23%) breast cancer deaths. In Cox proportional hazards models adjusting for lymph node status two parameters predicted longer survival, low NKA (HR 29 per LLU, p=0.003) and minimizing the illness adjustment (HR 0.64 per scale point, p=0.012). These data provide little evidence for a psychoneuroimmunological mechanism in the survival from breast cancer. While this study is limited due to small sample size, and therefore the possibility of inflated estimates, longer survival in those minimizing the illness is a finding consistent with recent studies; however, the counter-intuitive finding that high NKA predicts shorter survival may be a marker for current disease or response to treatments.