Radiation therapy in the multimodal treatment approach of Pituitary adenoma

• Published in: Strahlentherapie und Onkologie 2002-04, Vol.178 (4), p.173-186
• Main Authors: BECKER, Gerd, KOCHER, Martin, KORTMANN, Rolf-Dieter, PAULSEN, Frank, JEREMIC, Branislav, MÜLLER, Rolf-Peter, BAMBERG, Michael
• Format: Article
• Language: English
• Subjects: Acromegaly - etiology; Adenoma - mortality; Adenoma - radiotherapy; Adenoma - surgery; Adult; Biological and medical sciences; Brain Diseases - etiology; Brain Neoplasms - etiology; Brain Neoplasms - secondary; Child; Combined Modality Therapy; Cushing Syndrome - etiology; Dose Fractionation; Drug therapy; Endocrine glands; Female; Follow-Up Studies; Growth hormones; Humans; Male; Medical sciences; Neoplasm Recurrence, Local; Neoplasms, Radiation-Induced - etiology; Pituitary gland; Pituitary Neoplasms - mortality; Pituitary Neoplasms - radiotherapy; Pituitary Neoplasms - surgery; Postoperative Care; Prolactinoma - mortality; Prolactinoma - radiotherapy; Prolactinoma - surgery; Radiation therapy; Radiosurgery; Radiotherapy - adverse effects; Radiotherapy Dosage; Radiotherapy, Conformal; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Stroke - etiology; Time Factors; Tumors
• ISSN: 0179-7158; 1439-099X
• DOI: 10.1007/s00066-002-0826-x

Pituitary tumors are relatively uncommon, comprising 10-12% of all intracranial tumors. The treatment consisting of surgery, radiotherapy and drug therapy or a combination of these modalities is aimed at the control of tumor cell proliferation and--in endocrine active tumors--the reduction of hormone secretion. However, the slow proliferation characteristics of pituitary tumors necessitate long-term studies for the evaluation of the treatment results. In the last decade there has been continuous improvement in surgical procedures, radiotherapy techniques and drug generation. In this paper, literature will be reviewed to assess the role of modern radiotherapy and radiosurgery in the management of pituitary adenomas. Nowadays, magnetic resonance imaging for the definition of the target volume and a real three-dimensional (3-D) treatment planning with field conformation and the possibility for non-coplanar irradiation has to be recommended. Most groups irradiate these benign tumors with single doses of 1.8-2.0 Gy up to a total dose of 45 Gy or 50.4 Gy in extensive parasellar adenomas. Adenomas are mostly small, well circumscribed lesions, and have, therefore, attracted the use of stereotactically guided high-precision irradiation techniques which allow extreme focussing and provide steep dose gradients with selective treatment of the target and optimal protection of the surrounding brain tissue. Radiation therapy controls tumor growth in 80-98% of patients with non-secreting adenomas and 67-89% for endocrine active tumors. Reviewing the recent literature including endocrine active and non-secreting adenomas, irradiated postoperatively or in case of recurrence the 5-, 10- and 15-year local control rates amount 92%, 89% and 79%. In cases of microprolactinoma primary therapy consists of dopamine agonists. Irradiation should be preferred in patients with macroprolactinomas, when drug therapy and/or surgery failed or for patients medically unsuitable for surgery. Reduction and control of prolactin secretion can be achieved in 44-70% of patients. After radiotherapy in acromegaly patients somatomedin-C and growth hormone concentrations decrease to normal levels in 70-90%, with a decrease rate of 10-30% per year. Hypercortisolism is controlled in 50-83% of adults and 80% of children with Cushing's disease, generally in less than 9 months. Hypopituitarism is the most common side effect of pituitary irradiation with an incidence of 13-56%. Long-term overall risk for br