Limited predictive value of an acute test with subcutaneous octreotide for long-term IGF-I normalization with Sandostatin LAR in acromegaly.
OBJECTIVE
To study whether the growth hormone (GH) response after the subcutaneous administration 50 microg of octreotide (acute octreotide test) has any predictive value for long-term IGF-I normalization with Sandostatin LAR.


METHODS
Twenty four therapy-naive patients with active acromegaly were studied.


RESULTS
> 75% GH decrease in the acute octreotide test predicted long-term IGF-I normalization with Sandostatin LAR in 8/11 (73%) of patients. 3/13 (23%) patients with < 75% GH decrease in the acute octreotide test were long-term biochemically controlled with Sandostatin LAR. Using the > 75% GH reduction criterion, the sensitivity and specificity of this test for predicting long-term normalization of serum IGF-I with Sandostatin LAR treatment were 73% and 77%, respectively (positive and negative predictive values: 73% and 77%, respectively). 6/8 (75%) patients with GH suppression to levels < 1.1 microg/l and 9/16 (56%) patients with GH suppression to levels < 2 microg/l in the acute octreotide test showed normalization of serum IGF-I with long-term Sandostatin LAR treatment. The sensitivity and specificity of GH suppression < 1.1 microg/l for predicting of the long-term normalization of serum IGF-I with Sandostatin LAR therapy were 55% and 85%, respectively (positive and negative predictive values: 75% and 69%, respectively). The sensitivity and specificity of GH suppression < 2 microg/l for predicting of the long-term normalization of serum IGF-I with Sandostatin LAR therapy were 82% and 46%, respectively (positive and negative predictive values: 56% and 75%, respectively).


CONCLUSIONS
The acute octreotide is not recommended for clinical decision making with regard to long-term treatment using the long-acting somatostatin analog Sandostatin LAR in acromegaly.
Section of Endocrinology, Department of Internal Medicine, Erasmus MC, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands. w.w.deherder@erasmusmc.nl
Wouter W
WW
de Herder
H Rob
HR
Taal
Piet
P
Uitterlinden
Richard A
RA
Feelders
Joop A M J L
JA
Janssen
Aart-Jan
AJ
van der Lely
D000172:Acromegaly / Q000097:blood / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D003657:Decision Making; D005260:Female; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007279:Injections, Subcutaneous; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D011379:Prognosis; D012680:Sensitivity and Specificity
D018931:Antineoplastic Agents, Hormonal; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D015282:Octreotide