Modifying radical radiotherapy in high grade gliomas; shortening the treatment time through acceleration.

PURPOSE

To evaluate the efficacy and toxicity of accelerated radiotherapy in patients with primary high grade glioma, where acceleration is used as a means of delivering a shortened course of radical radiotherapy.

PATIENTS AND METHODS

Two-hundred and eleven patients with primary high grade glioma were treated at the Royal Marsden NHS Trust between 1987 and 1997 with accelerated radiotherapy (55 Gy in 34 fractions twice daily), to planning target volume (PTV) defined as enhancing tumour and a 3 cm margin. All had histologically confirmed high grade glioma (53 anaplastic astrocytoma, 137 glioblastoma multiforme, 4 gliosarcoma, 5 gemistocytic astrocytoma, 12 high grade astrocytoma not otherwise specified). The mean Karnofsky performance status (KPS) was 90 and median age was 54 years (range 19-77).

RESULTS

Of 211 patients entered, 201 were able to complete radiotherapy; 39 patients (19%) had deterioration in KPS during radiotherapy and this was transient in 11. Median survival of 211 patients was 10 months with 1 year, 2 year, and 3 year survival probabilities of 38%, 14%, and 8% respectively. Age and extent of excision were independent prognostic factors for survival. Previous comparison to matched cohort receiving 60 Gy in 30 daily fractions did not demonstrate significant survival difference.

CONCLUSION

Accelerated radiotherapy is a feasible treatment approach for patients with high grade glioma. The survival and functional outcome are comparable to conventional radiotherapy and the treatment is without serious acute toxicity. While acceleration of conventional dose irradiation could be tested in randomised studies, it is unlikely this approach would result in a clinically meaningful survival benefit. Accelerated radiotherapy therefore remains one of the ways of delivering radical irradiation in patients with high grade glioma. However, it adds complexity to what is a palliative treatment regimen and the rationale and advisability should be re-examined, particularly in terms of impact on quality of life, true patient preference, and health economic considerations.