Treatment of Low-Grade Gliomas — Watch and Wait or Give Post-Operative Radiation Immediately?
Treatment of Low-Grade Gliomas—Watch and Wait or Give Post-Operative Radiation Immediately?
Abstract & Commentary
By Matthew E. Fink, MD Dr. Fink is Vice Chairman, Professor of Clinical Neurology, Weill Medical College, Chief, Division of Stroke and Critical Care Neurology, New York-Presbyterian Hospital. Dr. Fink reports no consultant, stockholder, speaker's bureau, research, or other relationship related to this field of study.
Synopsis: In a randomized trial comparing immediate radiation therapy to delayed treatment in patients who underwent primary surgical resection of low-grade gliomas, overall survival was not significantly different between the 2 groups.
Source: van den Bent MJ, et al. Long-Term Efficacy of Early Versus Delayed Radiotherapy for Low-Grade Astrocytoma and Oligodendroglioma in Adults: The EORTC 22845 Randomized Trial. Lancet. 2005;366: 985-990.
The final results of a randomized European trial of immediate vs delayed radiosurgery for low-grade gliomas was recently reported by van den Bent and colleagues. Three hundred-eleven patients with a primary diagnosis of supratentorial and histologically proven low-grade astrocytoma, oligoastrocytoma, or oligodendroglioma were randomized after surgery to receive immediate radiation therapy (5 fractions of 1.8 Gy per week for 6 weeks) or delay of radiation therapy (control group) until there was proven progression by CT. The primary end points of the study were progression-free survival and overall survival. All patients had to be in good functional status (WHO performance status 0-2) at the time of randomization. An intention-to-treat analysis was performed to assess outcomes.
Median progression-free survival was 5.3 years in the early radiotherapy group and 3.4 years in the control group (hazard ratio 0.59, 95% CI, 0.45-0.77; P < 0.0001). However, overall survival was similar between groups: median survival in the radiotherapy group was 7.4 years, compared to 7.2 years in the control group (hazard ratio 0.97, 95% CI, 0.71 - 1.34; P < 0.872). At one year, seizures were better controlled in the early radiotherapy group, compared to the control group (25% vs 41% with seizures; P < 0.0329). At the time of tumor progression, biopsy demonstrated a high-grade tumor in 72% of the early radiation patients and 66% of patients in the control group.
Commentary
Immediate vs delayed radiation therapy for low-grade gliomas has been a debated recommendation for decades, and we applaud van den Bent and colleagues who undertook and completed this study. Their results indicate that both approaches are acceptable and depend on the clinical condition of the patient at time of presentation. A young patient without any symptoms or disability could be safely watched and treated at the time of tumor growth. If there are symptoms related to mass effect or frequent seizures, a more aggressive approach would be warranted.
However, there are still many questions raised by this report: 1) Does early radiation therapy cause long-term cognitive impairments? 2) Will MRI planning for conformal radiation therapy improve the overall results? 3) How does chemotherapy (temozolamide) change the long-term results of treatment for low-grade glioma? 4) Does more aggressive surgery at time of diagnosis improve outcome? The answers to these questions will require additional, cooperative, multicenter clinical trials.
In a randomized trial comparing immediate radiation therapy to delayed treatment in patients who underwent primary surgical resection of low-grade gliomas, overall survival was not significantly different between the 2 groups.Subscribe Now for Access
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