Medical treatment in acromegaly.

Abstract

Acromegaly is a rare disabling disorder that results in premature death. The excess mortality and morbidity are the result of prolonged elevation of growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels, and vigorous control of these improves well-being and restores life expectancy to normal. Recognition of the benefits of treatment has emphasised the need for optimal control of the GH/IGF-I axis. Transsphenoidal surgery is first-line therapy in the majority of patients; however, as most tumours are macroadenomas, cure rates are low. The role of radiotherapy is evolving and, although extremely effective at controlling tumour growth, it can take up to 15 years to control GH & IGF-I levels. In the interim, medical therapy is necessary. Dopamine agonists are inexpensive oral agents but, although most patients experience some benefit, GH and IGF-I levels are only normalised in around 35-40% of patients, and side effects are common. Somatostatin analogues are the gold standard of medical treatment. They can induce tumour shrinkage in a proportion of patients and can normalise the GH/IGF-I axis (at best) in approximately 65% of individuals; however, this leaves a significant cohort uncontrolled. The advent of the GH receptor antagonist pegvisomant provides the potential for IGF-I to be normalised in virtually every patient, but this novel form of therapy, which does not act on the pituitary, also raises many questions.