The effects of somatostatin analogue therapy on pituitary tumor volume in patients with acromegaly.
BACKGROUND
In nearly all cases, acromegaly is caused by excess GH from a pituitary adenoma, resulting in elevated circulating levels of GH and, subsequently, IGF-1. Treatment goals are to eliminate morbidity and restore the increased mortality to normal rates. Therapeutic strategies aim to minimize tumor mass and normalize GH and IGF-1 levels. Somatostatin analogues are the medical treatment of choice in acromegaly, as first-line or post-surgical therapy, and have proven efficacy in pituitary tumor volume reduction (TVR).


METHODS
Here we review the effects of somatostatin analogue therapy on pituitary tumor volume in patients with acromegaly.


RESULTS
TVR with somatostatin analogues may be mediated by direct anti-proliferative effects via activation of somatostatin receptors, or by indirect effects, such as angiogenesis inhibition, and is more pronounced when they are administered as first-line therapy. Various studies of first-line treatment with octreotide LAR have shown significant TVR in ≥73% of patients. First-line treatment with lanreotide Autogel has shown evidence of TVR, although more studies are needed. In a recent randomized, double-blind, 12-month trial in 358 medical-treatment-naïve acromegaly patients, significant TVR was achieved by 81% of patients administered pasireotide LAR and 77% administered octreotide LAR. Pre-operative somatostatin analogue therapy may also induce TVR and improve post-operative disease control compared with surgery alone. TVR is progressive with prolonged treatment, and decreased IGF-1 levels may be its best predictor, followed by age and degree of GH decrease. However, TVR does not always correlate with degree of biochemical control.


CONCLUSIONS
Somatostatin analogues (first- or second-line treatment) are the mainstay of medical therapy and, as first-line medical therapy, are associated with significant pituitary TVR in most patients.
Dipartimento di Medicina Clinica e Chirurgia, Sezione di Endocrinologia, Università Federico II di Napoli, via S Pansini 5, 80131, Naples, Italy. colao@unina.it.
Annamaria
A
Colao
Dipartimento di Medicina Clinica e Chirurgia, Sezione di Endocrinologia, Università Federico II di Napoli, via S Pansini 5, 80131, Naples, Italy.
Renata S
RS
Auriemma
Dipartimento di Medicina Clinica e Chirurgia, Sezione di Endocrinologia, Università Federico II di Napoli, via S Pansini 5, 80131, Naples, Italy.
Rosario
R
Pivonello
D000172:Acromegaly / Q000188:drug therapy* / Q000473:pathology; D000236:Adenoma / Q000188:drug therapy* / Q000473:pathology; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology* / Q000627:therapeutic use; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D015282:Octreotide / Q000494:pharmacology / Q000627:therapeutic use; D010456:Peptides, Cyclic / Q000494:pharmacology / Q000627:therapeutic use; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects*
D018931:Antineoplastic Agents, Hormonal; D010456:Peptides, Cyclic; C060347:lanreotide; D013004:Somatostatin; C517782:pasireotide; D015282:Octreotide
Acromegaly; Lanreotide; Octreotide; Pasireotide; Somatostatin analogue; Tumor volume