INTERSTITIAL 125-IODINE RADIOSURGERY OF LOW-GRADE GLIOMAS OF THE INSULA OF REIL

Between 1979 and 1991 67 patients with low-grade gliomas of the insula (of Reil) were treated with 125-iodine interstitial radiosurgery. Ret rospective analysis with a median follow-up of 55 months demonstrated a 5- and 10-year survival rate of 54% and 47%, respectively, for all l ow-grade gliomas treated and a 5- and 10-year survival rate of 57% for 49 patients with astrocytomas WHO grade II analysed separately. The m edian Karnofsky performance status of survivors was 90%. Malignant cha nge was the cause of death in 85%, failure to control tumour growth in the remaining cases. Multivariate analysis with a Cox proportional ha zard model identified solely the pre-operative Karnofsky performance s core of 70-80 vs. 90% as a prognostic factor for outcome (p = 0.001, r isk ratio 3.62), but not age, gender, tumour volume, length of disease before treatment, mode of implantation, or major vs. moderate or no s hrinkage of tumour volume after interstitial radiosurgery. Thus, 125-i odine radiosurgery yielded survival rates in these deep-seated insular gliomas comparable to those reported after surgery and radiation ther apy of lobar tumours. This was achieved with a low peri-operative mort ality and morbidity and at low costs.