Improved survival of patients with intracranial ependymomas by irradiation: Dose selection and field extension

Abstract

Intracranial ependymomas, treated with postoperative irradiation, have a 50% 5-year survival. Although this rate is good, the issue remains whether the quantity and quality of survival can be improved by the proper selection of treatment factors, i.e. field size and dose-time relationship. Factors influencing survival and the effect of dose and field selection are considered in 28 intracranial ependymomas. Nineteen spinal primaries are also presented for comparison. Only 10% of the patients treated with doses below 1350 rets are alive, vs. 56% of the patients treated with higher doses. Only 21% of the patients treated with partial brain irradiation survived, vs. 57% of those treated with whole brain irradiation. Although an apparent 5-year survival difference was found for the low-grade (63%) vs. high grade (13%) tumors, high-dose whole brain irradiation had a significant effect only on the survival of the high-grade tumors. Local recurrences accounted for the majority of therapeutic failures. Ten consecutive patients were treated with elective craniospinal irradiation and exhibited a 3-year survival of 70%, vs. 35% in those treated conventionally to the brain only. Elective craniospinal irradiation, advocated for the high-grade, particularly infratentorial, ependymomas, has currently yielded higher survival, lower recurrences, good tolerance, no complications, and excellent quality of survival. Further documentation of this treatment approach is suggested.