ADRENAL RECOVERY IN CUSHING DISEASE

NEW YORK (Reuters Health) - The three different subtypes of Cushing's syndrome offer different outlooks for recovery of adrenal function after surgery to remove the causative tumor, a new study suggests.

"Endocrinologists should inform their patients that recovery of adrenal function after curative surgery in pituitary, adrenal and ectopic Cushing's syndrome may be slow. Also, there is clearly a risk of permanent adrenal insufficiency. Patients need advice for self-management of adrenal insufficiency, including prevention of adrenal crisis," Dr. Martin Reincke, who directs the internal medicine department at the Ludwig Maximillian University of Munich in Germany, told Reuters Health by email.

Dr. Reincke and his team followed 91 patients for an average of more than eight years.

As reported online December 29 in the Journal of Clinical Endocrinology and Metabolism, ectopic Cushing's syndrome caused by neuroendocrine tumors had the best odds of recovery, with 82% of the 11 patients who had this subtype regaining adrenal function within five years. Average time to recovery was 0.6 years.

Cushing's disease and its characteristic tumor of the pituitary gland, the most common subtype, affected 54 patients in this study. Of those, 58% recovered adrenal function within five years and the average recovery time was 1.4 years.

Finally, adrenal Cushing's syndrome offered the least favorable odds of adrenal recovery at 38% within five years and an average recovery time of 2.5 years.

The p values were 0.001 for the comparison of the odds of recovering adrenal function at five years, and 0.002 for the comparison of median time to recovery.

"If confirmed by others, our data have clinical impact for the follow-up of patients after curative surgery: patients should be informed that adrenocortical function may remain impaired in benign conditions such as cortisol-producing adenoma," the researchers write.

The reason for the differences may have something to do with the patients' exposure to excess cortisol before treatment, Dr. Reincke said. Past research of patients who take glucocorticoids found that higher doses and longer exposures were linked to longer adrenal function recovery times.

"This sets the context for our work: patients with adrenal Cushing's syndrome have the lowest recovery rate of adrenal function after curative surgery. This suggests that exposure time to endogenous cortisol excess may have been longest in this entity. In contrast, the rapid onset of cortisol excess in the ectopic Cushing's syndrome leads to early diagnosis and treatment. Therefore, length of adrenal insufficiency is plausibly shortest in these patients," Dr. Reincke said.