Cushing's syndrome subtype affects postoperative time to adrenal recovery
In patients undergoing curative surgical tumor resection for Cushing’s syndrome, the time to recovery of adrenal function is contingent upon the underlying etiology of the disease, according to recent findings.
In the retrospective study, researchers reviewed case records of 230 patients with Cushing’s syndrome. All patients were seen at a tertiary care center in Munich between 1983 and 2014, whose cases were documented in the German Cushing’s Registry. Patients were divided into three subgroups of Cushing’s syndrome: Cushing’s disease, adrenal Cushing’s syndrome and ectopic Cushing’s syndrome.
After applying various exclusion criteria, the researchers identified 91 patients of the three subgroups who were undergoing curative surgery at the hospital. The patients were followed for a median of 6 years. The researchers defined adrenal insufficiency as the need for hydrocortisone replacement therapy, and collected this information from patient records and laboratory results.
The duration of adrenal insufficiency was calculated as the interval between successful surgery and the completion of hydrocortisone replacement therapy. Cushing’s syndrome recurrence was defined as biochemical and clinical signs of hypercortisolism.
The researchers found a significant difference between Cushing’s syndrome subtypes in the likelihood of regaining adrenal function within 5 years of follow-up: The probability was 82% in ectopic Cushing’s syndrome, 58% in Cushing’s disease and 38% in adrenal Cushing’s syndrome (P=.001). Among the 52 participants who recovered adrenal function, the median type to recovery also differed between subtypes and was 0.6 years in ectopic Cushing’s syndrome, 1.4 years in Cushing’s disease and 2.5 years in adrenal Cushing’s syndrome (P=.002).
An association also was found between younger age and adrenal recovery in the Cushing’s disease participants (P=.012).
This association was independent of sex, BMI, symptom duration, basal adrenocorticotropic hormone and cortisol levels. No association was seen between adrenal recovery and length of hypercortisolism or postoperative glucocorticoid replacement dosage.
“It is the main finding of this series that the median duration of tertiary adrenal insufficiency was dependent on the etiology of [Cushing’s syndrome]: It was shortest in the ectopic [Cushing’s syndrome], intermediate in [Cushing’s disease] and longest in adrenal [Cushing’s syndrome] caused by unilateral cortisol producing adenoma,” the researchers wrote. “The significant difference to [Cushing’s disease] is an unexpected finding since by biochemical means cortisol excess is generally less severe in adrenal [Cushing’s syndrome]. 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.”
Disclosure: The study was funded in part by the Else Kröner-Fresenius Stiftung.