Long-term follow-up results of combination therapy of surgery and gamma knife on pituitary tumor

Usefulness of the combination therapy for invasive pituitary tumor with surgery and gamma knife (GK) was evaluated on 17 cases followed for >2 years. Tumors involved ACTH cell adenoma, GH cell adenoma, mixed GH and PRL, purihormonal adenoma, gonadotrophic cell adenoma, GH cell adenoma and null cell adenoma, which were divided into I and II group since adverse effects by GK on the normal pituitary tissues could be evaluated according to tumor growth and abnormal hormone secretion. Irradiation was carried out to make the marginal dose of around 30 (15-35) Gy and center dose of 25-70 Gy on the gland, and marginal dose of <10 Gy on optic nerve. After GK, follow-up was done by pituitary hormone values, tests for sight and visual field and MRI examination. Hypopituitarism was seen in 67% with 100% remission of Cushing's disease. MRI revealed that the adenoma changed to fibrosis (type 1) with increasing Gd-enhancement or to cystic necrosis (type 2) without Gd-enhancement. Values for GH, cortisol and ACTH turned to normal ones. Thus the combination therapy was found useful. (K.H.)