Postoperative prognostic indicators of control of acromegaly

Changes in growth hormone basal levels and growth hormone dynamic tests such as thyrotropin-releasing hormone and luteinizing hormone-releasing hormone tests, and the glucose tolerance test were evaluated during a follow-up period of 1-17 years in 17 acromegalic patients. In these cases, mean growth hormone basal levels obtained 1-2 months after surgery had dropped to levels below 5 ng/mL. In 11 of the patients, the 1-2 months postoperative mean growth hormone basal levels were reduced to less than 3 ng/mL. In these patients, abnormal growth hormone responses to these dynamic tests were not present and mean growth hormone basal levels remained below 3.0 ng/mL during the follow-up period of 1-6 years. In contrast, the six other patients' 1-2 months postoperative mean growth hormone basal levels were between 3 and 5 ng/mL. Of these, four presented abnormal responses in at least one of these three dynamic tests 1-2 months postoperatively, and three exhibited a rise in growth hormone basal levels after intervals of 1-3.5 years after surgery. It is concluded that the restoration of normal growth hormone response to the dynamic tests is better related to the value of the mean growth hormone basal levels obtained 1-2 months postoperatively being less than 3 ng/mL rather than it is to the conventional criterion of the growth hormone basal levels being less than 5 ng/mL.