Is positive correlation between cortisol and met-enkephalin concentration in blood of women with breast cancer a reaction to stress before chemotherapy administration?

Abstract

The role of stress in the course of neoplastic diseases has been emphasised over the past few years. Organism defence in form of increased release of hormones, corticosteroids and endogenous opioids should be assessed as a particular form of adaptation. Interactions between stress hormones and others which may influence the growth of breast cancer cells are possible. In this study, the concentration of cortisol and met-enkephalin vis-à-vis growth hormone, insulin-like growth factor-I, prolactin, estradiol, progesterone and melatonin in blood of women with breast cancer before the first cycle of supplementary chemotherapy was compared to that of healthy women. In a group of patients with breast cancer, before the first cycle of chemotherapy, high hypercortisolemia and positive correlation between cortisol and met-enkephalin was observed which may be a result of stress at the beginning of such treatment. A negative correlation between prolactin and met-enkephalin in this group can indirectly testify to essential participation of endogenous opioids in hormonal regulation and can be a response to stress caused by beginning chemotherapy.