Radiosurgery of the metastatic brain tumours with gamma-knife.

The results of treatment of metastatic brain tumours by radiosurgery are reported. Twenty cases including lung (11), colon (5), breast (1), ovary (1), liver cancer (1) and malignant melanoma (1) were involved. Seven cases had single and 13 had multiple brain metastases. In total 55 lesions were evaluated after radiosurgery with the gamma-knife. Following localization with MR1 and dose planning, radiosurgery with marginal doses between 12 to 25 Gy (mean 18.9 Gy) was delivered. In the follow-up studies with MRI after 3 months, 29 out of 55 (52.7%) lesions showed significant shrinkage. In contrast 25 showed either no change (17) or central necrosis (8), and one was enlarged. Thus the tumour control at 3 months was 98.2%, and subsequently 96.6% at 6 months. Clinical symptoms and signs were improved in most cases, but were aggravated in four cases either by tumour recurrence or by radiation-induced oedema. Although the tumours treated with radiosurgery were well controlled, tumour recurrence in another sites occurred in 4 case, of which 3 were treated by 2nd radiosurgery with 2 successful tumour control. Complications were generally mild and transient. In summary stereotactic radiosurgery is valuable new treatment not only for solitary metastases, but also for multiple or recurrent ones.