Early postoperative growth hormone levels: high predictive value for long-term outcome after surgery for acromegaly

To explore the prognostic value of early - within 1 week - postoperative growth hormone (GH) measurements with regard to outcome after surgery for acromegaly in a short- and a long-term perspective.

Retrospective study of patients operated on between 1987 and 1998, including follow-up for up to 60 months.

University hospital.

Sixty-eight patients with acromegaly.

Pituitary surgery aiming at adenomectomy with preservation of pituitary function.

The effect of the operation was evaluated after 3 months, mostly by means of an oral glucose load or by insulin-like growth factor 1 (IGF-1). The specificity, sensitivity and the predictive values of an early postoperative mean GH concentration

Fifty patients (73.5%) showed a satisfactory effect at the evaluation 3 months postoperatively; 45 of these were followed between 12 and 60 months. Relapse was registered in five cases: 12, 12, 24, 24 and 48 months after surgery. In the long-term perspective, the predictive value of an early mean GH 4.8 mU L-1 had a 77.8% predictive value for persistent or recurrent disease, compared with 85.7% for persistently increased SmC/IGF-1 and 68.8% for an abnormal GH release after TRH 3 months after surgery. In the short-term perspective, the specificity and the predictive value of an early GH 4.8 mU L-1 had a 94.4% sensitivity but a predicative value of only 63.0% for an unsatisfactory effect.

Measurement of GH within 1 week after surgery is highly predictive for outcome of surgery for acromegaly. Specifically, an early mean GH 4.8 mU L-1 have a high sensitivity for persistent or recurrent disease in both the short- and long-term perspectives, but lower predictive value. The usefulness of the TRH test can be questioned.