[Radiotherapy of inoperable brain tumors in childhood]

Description and evaluation of radiotherapy of inoperable tumours of central nervous system. New possibilities in radiotherapy planning.

Between 1987 and 2004, 58 patients (30 boys and 28 girls, mean age 8.5+/-4.3 years) with brain stem tumours were treated with 6 MV or 9 MV photons of the linear accelerator, or with telecobalt. The doses administered ranged from 30 to 71.2 Gy; mean 51.7+/-8.4 Gy. Treatment in each case was performed according to CT- and/or MR-based radiotherapy plan. As of 2000, in case of 16 patients a 3D conformal irradiation plan has been prepared.

All patients were followed. The mean follow-up period was 21.8 months (range: 7 to 158 months). The mean duration of symptoms prior to diagnosis was 6.6+/-8.1 weeks (range: 1-52 weeks). Overall survival (OS) and progression-free survival (PFS) rates for all 58 patients were 39.9% and 21.2% at 1 years, 19.1% and 14.7% at 2 years, and 14.8% and 14.7% at 3 years respectively. The following factors were of prognostic influence on the OS in univariate analysis: duration of symptoms (< or = 2 months vs. >2 months, p=0.0081), radiological response (p < 0.0001) and clinical improvement (p = 0.0003). Prognostic factors for PFS were similar to those predicting for OS. Multivariate analysis revealed that the radiological (OS, p = 0.0034, PFS, p = 0.024) and clinical (OS, p = 0.026, PFS, p = 0.044) improvement 6 weeks after completion of radiotherapy were of prognostic significance.

Accurate field arrangement, precise patient fixation, and CT- and MR-based 3D conformal radiotherapy planning may result in better outcome of disease as well as minimal effect on surrounding normal tissues. Radiotherapy should be provided also for histologically not verified tumours. Sixty-eight percent of these patients had a transitory 20.6-month improvement, and 12.1% of them completely recovered.