Effects of mitotane on the hypothalamic-pituitary-adrenal axis in patients with adrenocortical carcinoma

Objective: Mitotane, a drug used to treat adrenocortical cancer (ACC), inhibits multiple enzymatic steps of adrenocortical steroid biosynthesis, potentially causing adrenal insufficiency. Recent studies in vitro have also documented a direct inhibitory effect of mitotane at the pituitary level. The present study was aimed to assess the hypothalamic-pituitary-adrenal axis in patients with ACC receiving mitotane. Design and methods: We prospectively enrolled 16 patients on adjuvant treatment with mitotane after radical surgical resection of ACC, who underwent standard hormone evaluation and h-CRH stimulation. A group of 10 patients with primary adrenal insufficiency (PAI) served as controls for the CRH test. Results: We demonstrated a close correlation between cortisol-binding globulin (CBG) and plasma mitotane levels, and a non-significant trend between mitotane dose and either serum or salivary cortisol in ACC patients. We did not find any correlation between the dose of cortisone acetate and either ACTH or cortisol levels. ACTH levels were significantly higher in patients with PAI than that in patients with ACC, both in baseline conditions (88.99 (11.04-275.00) vs 24.53 (6.16-121.88) pmol/L, P = 0.031) and following CRH (158.40 (34.32-275.00) vs 67.43 (8.8-179.52) pmol/L P = 0.016). Conclusions: The observation of lower ACTH levels in patients with ACC than that in patients with PAI, both in basal conditions and after CRH stimulation, suggests that mitotane may play an inhibitory effect on ACTH secretion at the pituitary levels. In conclusion, the present study shows that mitotane affects the HPA axis at multiple levels and no single biomarker may be used for the assessment of adrenal insufficiency

AME position statement on adrenal incidentaloma.

Objective: To assess currently available evidence on adrenal incidentaloma and provide recommendations for clinical practice. Design: A panel of experts (appointed by the Italian Association of Clinical Endocrinologists (AME)) appraised the methodological quality of the relevant studies, summarized their results, and discussed the evidence reports to find consensus. Radiological assessment: Unenhanced computed tomography (CT) is recommended as the initial test with the use of an attenuation value of <= 10 Hounsfield units (HU) to differentiate between adenomas and non-adenomas. For tumors with a higher baseline attenuation value, we suggest considering delayed contrast-enhanced CT studies. Positron emission tomography (PET) or PET/CT should be considered when CT is inconclusive, whereas fine needle aspiration biopsy may be used only in selected cases suspicious of metastases (after biochemical exclusion of pheochromocytoma). Hormonal assessment: Pheochromocytoma and excessive overt cortisol should be ruled out in all patients, whereas primary aldosteronism has to be considered in hypertensive and/or hypokalemic patients. The 1 mg overnight dexamethasone suppression test is the test recommended for screening of subclinical Cushing's syndrome (SCS) with a threshold at 138 nmol/l for considering this condition. A value of 50 nmol/l virtually excludes SCS with an area of uncertainty between 50 and 138 nmol/l. Management: Surgery is recommended for masses with suspicious radiological aspects and masses causing overt catecholamine or steroid excess. Data are insufficient to make firm recommendations for or against surgery in patients with SCS. However, adrenalectomy may be considered when an adequate medical therapy does not reach the treatment goals of associated diseases potentially linked to hypercortisolism