Stereotactic biopsy and brachytherapy of brain tumours.

This paper discusses 98 patients who had their cerebral lesions stereotactically biopsied. Modified Riechert-Mundinger instrumentation was employed. Of the 98 patients, eight received only biopsy and 90 were then interstitially radiated with iridium-192 (192Ir) custom stacked in afterloading catheters. The vast majority of brachytherapeutically treated lesions were anaplastic or malignant astrocytomas. There were some metastatic lesions, and in two instances the tumour occupied the infratentorial compartment. Two-thirds of the patients had received prior teletherapy; in the remainder, stereotaxis provided the initial diagnosis and brachytherapy the principal treatment. The survival data suggest reasons for optimism. Eighty percent of patients with anaplastic astrocytoma were alive 2 yr later, compared with 55% for those harbouring malignant astrocytomas. Since this is the largest database on this topic in the U.S.A., we are in the process of a more critical review. Complication rate is low. Diagnostic tissue was obtained in all instances. Delayed radionecrosis at the site of implant may aggravate neurological deficits when lesions involve functionally sensitive cortex or their pertinent underlying structures. Such reactions may appear 4-18 mnth after brachytherapy and are more likely to occur in patients who were previously radiated.