Immune and endocrine mechanisms of advanced cancer-related hypercortisolemia

Cancer progression depend on the immune and endocrine status of the patients. In particular, it has been observed that abnormally high levels of cortisol and/or an altered circadian secretion are associated with a poor prognosis in advanced cancer patients. The present study was performed to establish whether cancer-induced hypercortisolemia depends on an activation of the hypothalamic-pituitary axis or on a direct adrenal stimulation by inflammatory cytokines, such as IL-6, which have been proven to induce cortisol secretion.

The study included 50 metastatic solid tumor patients, who were evaluated before the onset of chemotherapy. Venous blood samples were collected in the morning to measure IL-10, IL-6, ACTH and cortisol serum levels. Moreover, to analyze its circadian secretion, cortisol levels were also evaluated on venous blood samples collected at 4.00 p.m.

Abnormally high morning levels of cortisol were observed in 19/50 (38%) patients. Moreover, a lack of a normal circadian rhythm of cortisol was seen in 8/50 (16%) patients. None of the patients showed high levels of ACTH. Abnormally high concentrations of IL-6 and IL-10 were present in 21/50 (42%) and in 14/50 (28%) patients, respectively. Mean serum levels of both IL-6 and IL-10 were significantly higher in patients with hypercortisolemia than in those with normal cortisol values (p<0.005 and p<0.001, respectively). According to previous clinical studies, these results confirm that the advanced neoplastic disease may be associated with enhanced cortisol levels and alterations of its circadian secretion. The lack of enhanced ACTH secretion excludes the possibility that the abnormal cortisol production is due to the activation of the hypothalamic-pituitary axis. On the contrary, the evidence of significantly higher concentrations of IL-6 in hypercortisolemic patients would suggest that cancer-related enhanced cortisol production may depend on a direct adrenal stimulation by IL-6 itself The well-demonstrated stimulatory role of cortisol on IL-10 production would explain the enhanced IL-10 secretion in hypercortisolemic patients.

Cancer-related hypercortisolemia would seem to depend on alterations of the feedback mechanisms between endocrine and cytokine secretions, occurring in the neoplastic disease.