Re-irradiation after gross total resection of recurrent glioblastoma : Spatial pattern of recurrence and a review of the literature as a basis for target volume definition

Strahlenther Onkol. 2017 Nov;193(11):897-909. doi: 10.1007/s00066-017-1161-6. Epub 2017 Jun 14.

Abstract

Background: Currently, patients with gross total resection (GTR) of recurrent glioblastoma (rGBM) undergo adjuvant chemotherapy or are followed up until progression. Re-irradiation, as one of the most effective treatments in macroscopic rGBM, is withheld in this situation, as uncertainties about the pattern of re-recurrence, the target volume, and also the efficacy of early re-irradiation after GTR exist.

Methods: Imaging and clinical data from 26 consecutive patients with GTR of rGBM were analyzed. The spatial pattern of recurrences was analyzed according to the RANO-HGG criteria ("response assessment in neuro-oncology criteria for high-grade gliomas"). Progression-free (PFS) and overall survival (OS) were analyzed by the Kaplan-Meier method. Furthermore, a systematic review was performed in PubMed.

Results: All but 4 patients underwent adjuvant chemotherapy after GTR. Progression was diagnosed in 20 of 26 patients and 70% of recurrent tumors occurred adjacent to the resection cavity. The median extension beyond the edge of the resection cavity was 20 mm. Median PFS was 6 months; OS was 12.8 months. We propose a target volume containing the resection cavity and every contrast enhancing lesion as the gross tumor volume (GTV), a spherical margin of 5-10 mm to generate the clinical target volume (CTV), and a margin of 1-3 mm to generate the planning target volume (PTV). Re-irradiation of this volume is deemed to be safe and likely to prolong PFS.

Conclusion: Re-irradiation is worth considering also after GTR, as the volumes that need to be treated are limited and re-irradiation has already proven to be a safe treatment option in general. The strategy of early re-irradiation is currently being tested within the GlioCave/NOA 17/Aro 2016/03 trial.

Keywords: Glioblastoma; Pattern of recurrence; Recurrence; Survival; Target volume.

MeSH terms

  • Adult
  • Aged
  • Brain Neoplasms / mortality
  • Brain Neoplasms / pathology
  • Brain Neoplasms / therapy*
  • Chemotherapy, Adjuvant
  • Combined Modality Therapy
  • Disease-Free Survival
  • Female
  • Glioblastoma / mortality
  • Glioblastoma / pathology
  • Glioblastoma / therapy*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Margins of Excision
  • Middle Aged
  • Neoplasm Recurrence, Local / mortality
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / therapy*
  • Radiotherapy Dosage
  • Radiotherapy, Adjuvant
  • Retreatment
  • Retrospective Studies
  • Tumor Burden* / drug effects
  • Tumor Burden* / radiation effects