Endocrine Abstracts

Acromegaly is a rare condition caused by overproduction of growth hormone (GH). Early diagnosis, optimal treatment and follow-up is essential for prognosis of patients with acromegaly. Surgery is first choice treatment of acromegaly. Cure rates range around 80% (63–100%) in GH secreting microadenomas, however only about 50% (40–72) in macroadenomas. If not curable, surgery has to be followed by other treatment modalities to achieve treatment goals that are according to Endocrine Society guidelines normalization of age adjusted IGF-I serum levels and random GH levels <1 μg/l. Medical tools for GH secreting adenomas include dopaminergic agonists, somatostatin analogues (SSA) and pegvisomant. Radiotherapeutic techniques include stereotactic radiosurgery and fractionated stereotactic radiotherapy. Cabergoline is effective usually in patients with modest hormonal activity only. In monotherapy normalizes IGF-I levels in approximately 30% of patients. However, it could be useful in combination with other drugs. SSA are probably most frequently employed in therapy of residual disease taking the advantage of combination of antisecretory and antitumoral affects. Hormonal normalization rate of ‘classical’ SSA, lanretoide and octreotide, is approximately 55%, moreover, they lead to significant shrinkage (>20% volume %) of tumorous tissue in approximately 57% of patients. In patients resistant to classical SSA, multiligand SSA pasireotide can be successfully applied and is effective in biochemical control in about 20% of previously resistant patients. Pasireotide is a GH receptor antagonist able to block GH biological action and decrease IGF-I production. It is effective in most patients in normalizing IGF-I levels depending on the dose used. However, it has no antitumoral affect. Radiotherapy is a third-line therapy according to Endocrine Society guideline. Advantage of radiotherapy is its antitumoral effect enabling to withdraw medical therapy in most patients. Proton beam therapy has recently been used for treatment of acromegaly.