Endocrine Abstracts

Surgery is the first-line treatment of patients with clinically non-functioning pituitary adenomas (NFA). Because of lack of clinical syndrome these tumours are diagnosed with a variable delay when patients suffer from compression symptoms (hypopituitarism, headache, visual field defects) due to the extension of the tumour outside the pituitary fossa. Surgery is followed by residual tumour tissue in most patients. In these cases, radiotherapy is generally used to prevent tumour re-growth. However, NFA cell membranes, in analogy with GH- and PRL-secreting adenoma, express somatostatin and dopamine receptors. Treatment with somatostatin analogues and dopamine-agonists induced some beneficial effects on visual field defects and was also followed by tumour shrinkage in a minority of cases. Dopamine-agonists seem to be more effective on tumour shrinkage than somatostatin analogues. More recently, a combination treatment with both somatostatin analogues and dopamine-agonists have been tested in a few patients with interesting results.

Lack of randomized, placebo-controlled trials prevents any conclusion on the efficacy of these drugs. In contrast, use of gonatotropin-releasing hormone analogues has been abandoned.