Adverse long-term effects of brain radiotherapy in adult low-grade glioma patients

Abstract

To the Editor: We were struck by an article in Neurology 1 suggesting adverse effects of radiation therapy in patients with “low grade glioma.” This report, based on an initial experience in 160 patients, provides retrospective evidence that for survivors there is some risk of cognitive dysfunction in patients who for the most part received radiation therapy using techniques that have been abandoned for more than 10 years. The authors note themselves that this retrospective report “cannot exclude the possibility that patients with poor performance and more anaplastic tumors were selected for radiation therapy.” We believe the striking issue, not discussed by the current report, was the overall very poor outcome for patients with low-grade glioma. It should be noted that the patients included were Grade 1 (pilocytic astrocytoma) and represented a mixed series of astrocytic, oligoastrocytic, or pure oligodendrogial tumors, some of which contained anaplastic foci (clearly not low-grade). Patients were treated with a variety of techniques. At the time of the review, the vast majority of the patients had died of progression of their disease, and the median survival was approximately 7 years. This is in line with other reports detailing the dismal prognosis of patients erroneously called “low-grade glioma patients.” Most of these patients had whole-brain radiation therapy, a technique that was abandoned in clinical trials for malignant glioma over a decade ago. The type of radiation therapy (linear accelerator, cobalt, etc.) is not specified. The influence of resection cannot be defined. The cause of death is also …