Updates in the Medical Treatment of Pituitary Adenomas

Pituitary adenomas represent approximately 15% of brain tumors; incidence is significantly on the increase due to widespread use of magnetic resonance imaging. Surgery remains the first-line treatment for most tumors overall. The role of dopaminergic agonists (DAs) and somatostatin receptor ligands (SRLs) in the treatment of pituitary adenomas is quite well established for prolactinomas and growth hormone (GH) excess. However, over the last decade new multi-receptor binding SRLs are increasingly used for treatment of acromegaly and Cushing's disease. SRLs/DA chimeric compounds seem to have enhanced potency and efficacy when compared to that of individual SRLs or DA receptor agonists according to preclinical data. However, following negative results, more research is needed to determine if this interesting mechanism will translate into positive clinical effects for acromegaly patients. Furthermore, new agents that block adrenal steroidogenesis have been developed in phase III clinical trials for Cushing's disease and several new compounds working at the pituitary level and/or blocking the glucocorticoid receptor are also in development. Combination therapy of drugs with similar or different mechanisms (possibly synergistic) are also on the increase. A growing awareness regarding all mechanisms involved in both control of pituitary secretion and cellular proliferation might allow for sole medical treatment of pituitary adenomas, especially macroadenomas, rather than surgery and/or radiation therapy, in the future. Moreover, the underlying decision on how to treat patients with pituitary adenomas should be individualized on a case-by-case basis with not only a goal of tumor shrinkage and biochemical control, but also of improving patients' quality of life.