Biochemical and clinical benefits of unilateral adrenalectomy in patients with subclinical hypercortisolism and bilateral adrenal incidentalomas

Objective: The treatment of subclinical hypercortisolism in patients with bilateral adrenal incidentalomas (AI) is debatable. We aimed to compare the biochemical and clinical outcome of unilateral adrenalectomy vs a conservative approach in these patients. Design: Retrospective study. Methods: The study included 33 patients with bilateral AI; 14 patients underwent unilateral adrenalectomy of the largest lesion (surgical group), whereas 19 patients were followed up (follow-up group). At baseline and at each follow-up visit, we measured 0800 h plasma ACTH, midnight serum cortisol (MSF), 24-h urinary-free cortisol (UFC) and serum cortisol following a standard 2-day low-dose-dexamethasone-suppression test (LDDST). We evaluated the following comorbidities: arterial hypertension, impaired glucose tolerance or diabetes mellitus, dyslipidemia and osteoporosis. Results: Baseline demographic, clinical characteristics and the duration of follow-up (53.9 +/- 21.3 vs 51.8 +/- 20.1 months, for the surgical vs the follow-up group) were similar between groups. At the last follow-up visit the surgical group had a significant reduction in post-LDDST cortisol (2.4 +/- 1.6 vs 6.7 +/- 3.9 mu g/dl, P=0.002), MSF (4.3 +/- 2 vs 8.8 +/- 4.6 mg/dl, P=0.006) and 24-h UFC (50.1 +/- 21.1 vs 117.9 +/- 42.4 mu g/24 h, P=0.0007) and a significant rise in mean +/- S.D. morning plasma ACTH levels (22.2 +/- 9.6 vs 6.9 +/- 4.8 mu g/ml, P=0.002). Improvement in co-morbidities was seen only in the surgical group, whereas no changes were noted in the follow-up group. Conclusions: Our early results show that removal of the largest lesion offers significant improvement both to cortisol excess and its metabolic consequences, without the debilitating effects of bilateral adrenalectomy. A larger number of patients, as well as a longer follow-up, are required before drawing solid conclusions.