What is the first line treatment for Cushing's disease caused by a pituitary adenoma?

Transphenoidal surgery is considered the first-line treatment for Cushing's disease caused by a pituitary adenoma. This surgical approach aims to directly remove the tumor responsible for excessive cortisol production. By excising the pituitary adenoma, the source of adrenocorticotropic hormone (ACTH) overproduction is eliminated, leading to a reduction in cortisol secretion and alleviating the symptoms of Cushing's disease.

This method is preferred over other treatments because it addresses the underlying cause rather than just managing the symptoms. Transphenoidal surgery has a high success rate, especially when performed by experienced endocrine surgeons, and it can result in a significant improvement in patient outcomes.

Other treatment options may be considered depending on individual circumstances, but they do not serve as initial interventions in the case of a pituitary adenoma. Corticosteroid therapy is generally not appropriate, as it could exacerbate the condition by further increasing cortisol levels. Adrenalectomy is typically reserved for cases where the disease is caused by an adrenal tumor, while radiation therapy is usually employed in cases where surgery is not an option or after surgery if the tumor is not fully removed, leading to a second-line treatment status.