The objective of this study is to evaluate, in acromegalic patients with disease persistence after surgery who are treated with somatostatin analogues, the histopathological, clinical, morphological and biochemical factors which are predictive of hormonal control.

Inclusion Criteria:

• Acromegalic patients with persistent disease (growth hormone ≥ 1ng/ml following oral glucose tolerance test and/or insulin like growth factor 1 above the normal range for sex and age) 3 to 6 months after transsphenoidal or transfrontal surgery

Exclusion Criteria:

• Patients not contributing enough material for a tumour histopathological study
• Patients who have received radiation therapy or will receive it during the observational study period
• Patients who are being treated, or in whom treatment is anticipated, with either a dopaminergic agonist or a growth hormone receptor antagonist
• Patients with a history of hypersensitivity to somatostatin analogues

Acromegalic patients with persistence of the disease who attend specialized visits (Endocrinologist) at the Spanish hospitals.