The results of radiosurgical management of 139 single cerebral metastases.

Abstract

Between March 1984 and June 1993, linac radiosurgery was performed in 139 patients for single brain metastases, using the non-invasive (Greitz-Bergström) head fixation system. This atraumatic system was utilized for subsequent stereotactic CT/NMR staging to obtain strictly comparable neuro-imaging. Thus, tumour response was evaluated precisely and radiosurgery repeated (straight after the diagnostic sitting), as needed. No hospitalization or anaesthesia was necessary. The 25 mm target was the maximum size to avoid the risk of radiation induced reactions. In metastases exceeding this limit single doses were directed at more than one target at the same session. Focusing upon single or multiple targets was facilitated by 3-D stereotactic NMR. The results after one single sitting were compared with those obtained after staged sittings in the same patients. Radiosurgery achieved disappearance or shrinkage of the metastasis with resolution of the oedema and mid-line shift in 86% of the 139 patients treated. In 47% of them, however, the success was the result of repeat radiosurgery and staged sittings. The non-invasive procedure is the keystone to optimize the radiosurgical results.