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


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


METHODS
University hospital.


METHODS
Sixty-eight patients with acromegaly.


METHODS
Pituitary surgery aiming at adenomectomy with preservation of pituitary function.


METHODS
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 </= 4.8 mU L-1, as well as of the GH response to thyrotropin-releasing hormone (TRH) 3 months after surgery, were calculated with regard to outcome of the operation in both 3-month and long-term perspectives.


RESULTS
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 was 93.6% with regard to a satisfactory effect of surgery, compared with 90.2% for a normalized somatomedin C (SmC)/IGF-1 and 90.0% for an absent GH response after TRH. 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 were 77.3 and 97.1%, respectively. Early GH > 4.8 mU L-1 had a 94.4% sensitivity but a predicative value of only 63.0% for an unsatisfactory effect.


CONCLUSIONS
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 is as predictive for a satisfactory effect of treatment as a normalized IGF-1 3 months after surgery. Early postoperative GH values > 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.
Valdemarsson
S
S
Department of Internal Medicine, Lund University Hospital, Malmö, Sweden. stig.valdemarsson@skane.se
Ljunggren
S
S
Bramnert
M
M
Norrhamn
O
O
Nordström
C H
CH
D000172:Acromegaly / Q000097:blood* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I