State of the science: stress, inflammation, and cancer.

Diagnosis with a life-threatening illness such as cancer is almost universally experienced as stressful. The construct of stress has received substantial consideration as a correlate or predictor of psychological and health outcomes (Andersen et al., 2004) and has often been conceptualized within a stress and coping framework (Lazarus & Folkman, 1984). Biobehavioral factors have long been thought to affect many health processes. The relationship between inflammation of stress and cancer originated centuries ago and is now recognized as a facilitating characteristic of cancer (Mantovani, Allavena, Sica, & Balkwill, 2008). In addition, stress and the stress response are probable mediators of the effects of psychological factors on cancer, and specifically on progression of cancer (Powell, Tarr, & Sheridan, 2013). A substantial amount of new research activity has enlightened scientists and clinicians on the neuroendocrine regulatory function of physiologic pathways in cancer growth and progression (Lutgendorf & Sood, 2011). However, in spite of considerable research over the past several decades, inconsistent data remain a challenge in establishing evidence-based pathways between behavioral risk factors and cancer initiation.