Clinical and dosimetric study of radiotherapy for glioblastoma: three-dimensional conformal radiotherapy versus intensity-modulated radiotherapy

Abstract

Background and purpose: We aimed to compare three-dimensional conformal radiotherapy (3D-CRT) with intensity-modulated radiotherapy (IMRT) for the treatment of glioblastoma.

Materials and methods: Retrospective study of 220 patients with glioblastoma, treated with 3D-CRT or IMRT, with or without surgery. Dosimetric parameters as well as clinical and survival data for the two techniques were analyzed and compared.

Results: The median conformity index was 1.53 (range 0-2.69) for 3D-CRT and 1.25 (range 0.97-2.01) for IMRT, p < 10^-4. The median homogeneity index was 0.10 (range 0.03-0.32) for 3D-CRT and 0.07 (range 0.03-0.18) for IMRT, p < 10^-4. There were significantly fewer acute grade 1 and 2 neurological toxicities in the IMRT group especially for edema (1.3 versus 12.4%, p = 0.017), concentration disorders (6.6 versus 19.9%, p = 0.003) and consciousness disorders (2.6 versus 13.2%, p = 0.002) although IMRT patients had a significantly worse pre-treatment neurological status than 3D-CRT patients. Median survival was 16.0 months (range 11.9-17.8) for IMRT and 13.4 months (range 11.7-15.7) for 3D-CRT patients (p = 0.542).

Conclusion: IMRT improved target conformity and reduced neurological toxicities for patients with glioblastomas.

Keywords: 3D conformational radiation therapy; Clinical outcomes; Dosimetric outcomes; Glioblastoma; Intensity-modulated radiation therapy.