A. Colao et al., Long-term effects of depot long-acting somatostatin analog octreotide on hormone levels and tumor mass in acromegaly, J CLIN END, 86(6), 2001, pp. 2779-2786
The effects of a 12- to 24-month treatment with depot long-acting octreotid
e (OCT-LAR) on hormone profile, tumor mass, and clinical symptoms were repo
rted in 36 patients with active acromegaly [GH, 34.2 +/- 5.6 mug/L; insulin
-like growth factor I(IGF-I), 784.5 +/- 40.4 mug/L]. Fifteen patients were
de novo whereas 21 had previously undergone unsuccessful surgery.
Serum GH (P < 0.0001) and IGF-I levels (P < 0.0001) significantly decreased
as early as after the first injection of OCT-LAR and progressively decline
d during the 12-24 months of treatment both in de novo and in operated pati
ents. At the last follow-up, GH hypersecretion was controlled (less than or
equal to2.5 mug/L) in 69.4% whereas normal IGF-I levels were achieved in 6
1.1% of patients. GH and IGF-I suppression during OCT-LAR treatment was sim
ilar in de novo and operated patients as shown by nadir GH (2.3 +/- 0.6 vs.
2.2 +/- 0.6 mug/L) and IGF-I (323.1 +/- 34.9 vs. 275.5 +/- 33.0 mug/L), pe
rcent suppression of GH (92.7 +/- 2.0 vs. 85.9 +/- 3.3%) and IGF-I (57.4 +/
-: 4.9 vs. 61.5 +/- 4.6%), and prevalence of GH (73.3 us. 76.2%) and IGF-I
(53.3 us. 71.4%) control. A decrease in tumor volume was observed in 12 of
15 de novo patients, whereas no shrinkage was detected in 4 of 9 operated p
atients. No patient had tumor reexpansion during OCT-LAR treatment. Signifi
cant clinical improvement was obtained in all patients; heart rate, systoli
c blood pressure, and diastolic blood pressure significantly decreased in t
he entire population. A mild but significant increase of blood glucose leve
ls, followed by a decrease of serum insulin levels, was observed after 3 mo
nths of treatment: this effect subsided with treatment continuation. OCT-LA
R treatment was well tolerated by most patients.
In conclusion, long-term treatment with OCT-LAR was effective in controllin
g GH and IGF-I hypersecretion in most patients with acromegaly, when applie
d either as primary therapy or as adjunctive therapy after surgery. Tumor s
hrinkage was observed in de novo patients during OCT-LAR treatment, suggest
ing that it can be successfully applied as primary therapy in patients bear
ing invasive tumors, who are less likely to be cured after surgery.