Early postoperative evaluation in patients with Cushing's disease: usefulness of ovine corticotropin-releasing hormone test in the prediction of recurrence of disease.

In the attempt to identify parameters that might predict the risk of recurrence of Cushing's disease at an early stage after successful pituitary microsurgery, we evaluated retrospectively the usefulness of an early postoperative determination of morning plasma and urinary cortisol levels and of adrenocorticotropin (ACTH) and cortisol responses to ovine corticotropin-releasing hormone (oCRH) stimulation in 30 patients with pituitary-driven Cushing's disease followed up for 9 months to 10 years after pituitary surgery. At an early postoperative evaluation, while off substitutive therapy, 30 patients, out of 36 treated by pituitary microsurgery for Cushing's disease, were considered in remission on the basis of subnormal (21 patients), low-normal (eight patients) or normal (one patient) morning plasma and urinary cortisol levels, whereas six patients with supranormal urinary cortisol excretion were considered as surgical failures. The plasma ACTH response to oCRH was subnormal (17 patients) or normal (four patients) in 21 patients (Group 1) and supranormal in nine patients (Group 2). All of the six patients with persistence of Cushing's disease had supranormal ACTH response to oCRH. Basal and oCRH-stimulated cortisol levels were subnormal in 25 out of 30 patients considered in remission. During long-term evaluation, six patients had recurrence of Cushing's disease 9 months to 5 years after surgery; their early postoperative mean basal morning plasma and mean urinary cortisol were higher than those recorded in patients who did not relapse, although a wide overlap between subjects was evident. In five out of these six patients urinary cortisol excretion had decreased to almost undetectable values during low-dose dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)