Response of Human Malignant Gliomas and CNS Tissue to 125I Brachytherapy: A Study of Seven Autopsy Cases

Abstract

The effects of 125 I brachytherapy on malignant human gliomas and CNS tissue was studied in seven patients dying after such treatment. All the patients had biopsy proven malignant gliomas and all had failed therapy with external radiation and chemotherapy. Isodose curves of the brachytherapy were superimposed on the sectioned brain and sections prepared to determine the effects of various dose levels on tumor and CNS tissue. Tumor recurred in six of seven patients and was within 2.0 sm of the initial tumor site as determined by computed tomographic (CT) and radionuclide (RN) studies in five of six patiens. There were three zones of tissue response: 1. a central zone of complete to almost complete demyelination with extensive tissue destruction but preservation of altered vascular and astrocytic elements with a variable inflammatory and reactive response, and, 3. a zone of incomplete and irregular demyelination also with gliosis and inflammatory-reactive response.