Value of early postoperative random growth hormone levels and nadir growth hormone levels after oral glucose tolerance testing in acromegaly

• Published in: Growth hormone & IGF research Vol. 41; pp. 64 - 70
• Main Authors: Rotermund, Roman, Burkhardt, Till, Rohani, Zaina, Jung, Roman, Aberle, Jens, Flitsch, Jörg
• Format: Journal Article
• Language: English
• Published: Scotland Elsevier Ltd 01.08.2018
• Subjects: Acromegaly; Acromegaly - surgery; Adenoma - surgery; Adult; Aged; Aged, 80 and over; Biomarkers - analysis; Early postoperative oral glucose tolerance testing; Female; Follow-Up Studies; Glucose Tolerance Test - methods; Growth hormone; Human Growth Hormone - blood; Humans; IGF1; Incidence; Insulin-Like Growth Factor I - analysis; Male; Middle Aged; Postoperative Complications - blood; Postoperative Complications - diagnosis; Postoperative Complications - epidemiology; Prognosis; Prospective Studies; Young Adult; Acromegaly; Early postoperative oral glucose tolerance testing; IGF1; Growth hormone
• ISSN: 1096-6374; 1532-2238
• DOI: 10.1016/j.ghir.2018.03.002

There is no ideal marker to identify residual tumor tissue after surgery in patients with acromegaly. The purpose was to elucidate if early postoperative hormone testing gives reliable information regarding complete resection of a GH-producing pituitary adenoma. Fourty-eight patients undergoing surgery for acromegaly from 04/2013-05/2014 were prospectively examined for random GH, IGF1, and GH levels after oral glucose tolerance testing (OGTT) in the early postoperative phase and on follow-up. Criterion for inclusion was a minimum follow-up of one year for each patient with respect to remission. Thirty-three patients showed GH suppression below 1 μg/l after OGTT in the early postoperative phase. Follow-up GH, IGF1 and OGTT tests confirmed the initial findings in 30 patients. The three remaining patients showed biochemical signs of persisting acromegaly. In the remaining 15 patients early postoperative GH suppression was above 1 μg/l. Of those, six patients went into remission during follow-up, nine patients without postoperative GH suppression <1 μg/l remained acromegalic. GH suppression to <1 μg/l as well as random GH levels below 1 μg/l in the early postoperative phase seem to be of good positive predictive value for long-term remission. However, several patients without suppression of GH to <1 μg/l in the early postoperative OGTT went into delayed remission. These results have to be taken into account prior to initiation of further therapy. •spont. GH and GH < 1 μg/l in early postoperative OGTT have a high pos. predictive value for remission.•GH suppression during early post-operative OGTT below 0.4 μg/l may even be better.•There is no safe marker for surgical failure unless GH > 3.5 μg/l.•Careful monitoring of patients for up to 12 months after surgery is required.