ABSTRACT
UNLABELLED: In the early postoperative period of Cushing's disease patients, desmopressin may stimulate ACTH secretion in the remnant corticotrophic tumour, but not in nontumour suppressed cells. OBJECTIVE: The aim of this study is to evaluate the serum cortisol responses to desmopressin after pituitary surgery, establishing an optimal cut-off for absolute increment (Delta) of serum cortisol (F) suitable to predict recurrence risk. DESIGN: Retrospective case record study. PATIENTS: Fifty-seven Cushing's disease patients submitted to pituitary surgery and desmopressin stimulation in the early postoperative with a long-term follow-up (20-161 months) were studied. METHODS AND MEASUREMENTS: Serum cortisol levels after desmopressin test (10 microg i.v.) 15-30 days after adenomectomy were used to determine DeltaF (absolute increment of F: F peak - F baseline). Sensitivity and specificity of DeltaF were calculated and a ROC curve was performed to establish an optimal cut-off for DeltaF to predict recurrence risk. RESULTS: Fifteen patients had immediate postoperative failure (basal F > 165 nmol/l; 6 microg/dl) and one patient was lost during the follow-up. Forty-one patients achieved initial remission and were followed-up. Five of 11 patients who recurred had DeltaF > 193 nmol/l (7 microg/dl), but none of 30 patients who remained in prolonged remission showed DeltaF > 193 nmol/l after postoperative desmopressin stimulation. CONCLUSIONS: Persistence of cortisol response (DeltaF > 193 nmol/l) to desmopressin in the early postoperative period can help to identify Cushing's disease patients with initial remission who present risk for later recurrence.
