脳下垂体腺腫の治療成績の検討

RESULTS OF THE TREATMENT FOR PITUITARY ADENOMAS

Ｉ．はじめに

　脳下垂体腺腫は，頭蓋内良性腫瘍の中で，髄膜腫に次いで多く，われわれは，1971年5月までに，hyperpla—siaを含め360例を経験している。これは，教室の2.800例の頭蓋内新生物（真正腫瘍）の12.8％に相当する重要な腫瘍である。

　この脳下垂体腺腫に対す治療方法は，眼症候のみられないeosinophilic adenoma （acromegaly）をのぞいて，現在，脳神経外科領域ではほぼ標準化されたと考えてよいであろう。すなわち，開頭術による腫瘍の被膜内摘出術（intracapsular removal）につづいて，⁶⁰Co照射を主とする放射線療法の併用である。しかも，この術後放射線療法は腫瘍の再発を著明に抑えることができるため，あえて危険をおかして，腫瘍被膜まで摘出する必要はないとされてきた。しかしながら，一方では，放射線療法に伴なう合併症が指摘され，また，術後放射線併用療法によっても，確実に腫瘍の再発を予防できない点などからも，従来の治療法には問題点が残されていた。

The authors have as yet experienced 360 cases of pituitary adenomas during these 35 years since 1936 year ; these are 282 chromophobe adenomas, 44 eosinophilic adenomas or hyperplasias, 15 mixed adenomas, 18 malignant adenomas and a basophilic hyperplasia.

Results of the treatment for these pituitary adenomas are discussed. The cases before 1958 year were generally treated by the surgical intra-capsular removal by the transfrontal route, and almost all cases after 1958 year were treated bythe surgery with the postoperative irradiation. The recent 15 cases were operated on with the help of the microsurgical technique.

The frequency of the hospital death in initial cases by the intracranial approach is 8.6% and it increases in recurrent cases.

The effects of the postoperative irradiation are examined. As for the improvement of the visual acuity after the treatment, the postoperative ir-radiation gets better results (70.7%) compared with the surgery alone (63.8%).

The improvement of the visual field is also better in cases of the postoperative irradiation (69.8%) compared with those of the surgery alone (56.3%).

But in over half of the cases of the improved visual acuity or visual field, the improvement initiat-ed already before the beginning of the irradiation, and so the authors come to the conclusion that the effect of the postoperative irradiation for the im-provement of the visual acuity or visual field can not estimated so much.

On the other hand, the effect of the postoperative irradiation for the prevention of the recurrence ismarked. The frequency of 5-year-recurrence in cases of the surgery alone is 26.0% and that in cases of the postoperative irradiation is 13.6% ex-cluding malignant adenomas. Comparing the fre-quency of the recurrence among the cases with the interval over 5 years after the treatment, the posto-perative irradiation (14.4%) has less frequent re-currence than the surgery alone (39.0%) excluding malignant adenomas.

The complications of the irradiation were observed in 7 cases in 223 irradiations (3.1%), of which 2 cases died directly from the complication, one from the hemorrhage within the tumor and one from the radiation necrosis.

With the microsurgery, the so-called total removal of the chromophobe adenomas is feasible and in-dicated when the tumor is moderately large. And in not so large tumors, the selective hypophysectomy releaving the normal pituitary gland is recom-mended. The transsphenoidal hypophysectomy for acromegaly is easily performed with the use of the operating microscope.