Treatment Option Overview
The goals of treatment of pituitary adenomas include normalization of hormonal secretion (i.e., normalization of hypersecretion and improvement in hypofunction) and resolution or cessation of the progression of neurological defects.
Standard treatments for patients with pituitary tumors include:
- Radiation therapy.
- Medical therapy.
- A combination of surgery, radiation therapy, and medical therapy.
The treatment of choice must be individualized and is dictated by the type of tumor, the nature of the excessive hormonal expression, and whether or not the tumor extends into the brain around the pituitary.[1,2]
The transsphenoidal microsurgical approach to a pituitary lesion is the most widely employed surgical approach to pituitary lesions and represents a major development in the safe surgical treatment of both hormonally active and nonfunctioning tumors.[3-5] This approach is often successful in debulking tumors, even those that have a significant suprasellar extension.
A contraindication to this approach includes tumors with a significant suprasellar extension with an hourglass-shaped narrowing between the intrasellar and suprasellar component because blind attempts to reach the suprasellar tumor may lead to cerebral damage. In addition, an infection in the sphenoid sinus is potentially a contraindication to the transsphenoidal approach. In such cases, craniotomies via a pterional or subfrontal approach may be performed. Rapid deterioration of vision is an immediate indication for surgery to relieve pressure produced by an expanding tumor mass, except in the case of macroprolactinomas (where intensive observation with a patient on dopaminergic agonists may be an acceptable alternative). Progressive deterioration of visual fields is often the primary neurological criterion on which surgical management decisions are based.
Conventional radiation therapy is an effective adjunct to the treatment of pituitary tumors. The advantages of radiation therapy are that it is noninvasive and suitable for surgically high-risk patients. The clinical and biochemical response, however, is slow and may require from 2 years to 10 years for complete and sustained remission. In addition, radiation therapy carries a substantial risk of hypopituitarism (i.e., approximately 30% at 10 years).
Hormone-secreting tumors may be treated with surgery or radiation therapy. Surgical therapy is the treatment of choice for growth hormone-(GH) producing, adrenocorticotropic hormone-(ACTH) producing, and endocrine-inactive adenomas. GH-secreting tumors can be treated with somatostatin analogues, dopamine analogues, and the newer GH-receptor antagonists, such as pegvisomant. Ketoconazole, an inhibitor of steroidogenesis, is considered the first drug of choice as adjunctive medical therapy for ACTH-producing tumors. Somatostatin analogues are the drugs of choice for treatment of thyroid-stimulating, hormone-producing adenomas; however, the efficacy of treatment may wane with time.
The natural history of growth hormone-secreting and ACTH-secreting pituitary tumors is usually one of slowly progressive enlargement. Microprolactinomas, however, often remain unchanged, or decrease in size over time, and have been observed to undergo complete, spontaneous resolution on occasion.
Treatments under clinical evaluation for patients with pituitary tumors include:
- Stereotactic radiation surgery.
- Asa SL, Ezzat S: The cytogenesis and pathogenesis of pituitary adenomas. Endocr Rev 19 (6): 798-827, 1998. [PUBMED Abstract]
- Landman RE, Horwith M, Peterson RE, et al.: Long-term survival with ACTH-secreting carcinoma of the pituitary: a case report and review of the literature. J Clin Endocrinol Metab 87 (7): 3084-9, 2002. [PUBMED Abstract]
- Yeh PJ, Chen JW: Pituitary tumors: surgical and medical management. Surg Oncol 6 (2): 67-92, 1997. [PUBMED Abstract]
- Hardy J: Transsphenoidal microsurgery of the normal and pathological pituitary. Clin Neurosurg 16: 185-217, 1969. [PUBMED Abstract]
- Hardy J: Transsphenoidal hypophysectomy. J Neurosurg 34 (4): 582-94, 1971. [PUBMED Abstract]
- Levy A: Pituitary disease: presentation, diagnosis, and management. J Neurol Neurosurg Psychiatry 75 (Suppl 3): iii47-52, 2004. [PUBMED Abstract]
- Laws ER, Sheehan JP, Sheehan JM, et al.: Stereotactic radiosurgery for pituitary adenomas: a review of the literature. J Neurooncol 69 (1-3): 257-72, 2004 Aug-Sep. [PUBMED Abstract]