Velocity of radial expansion of contrast-enhancing gliomas and the effectiveness of radiotherapy in individual patients: a proof of principle

Clin Oncol (R Coll Radiol). 2008 May;20(4):301-8. doi: 10.1016/j.clon.2008.01.006. Epub 2008 Mar 4.

Abstract

Aims: The initial aims were to use recently available observations of glioblastomas (as part of a previous study) that had been imaged twice without intervening treatment before receiving radiotherapy in order to obtain quantitative measures of glioma growth and invasion according to a new bio-mathematical model. The results were so interesting as to raise the question whether the degree of radio-sensitivity of each tumour could be estimated by comparing the model-predicted and actual durations of survival and total numbers of glioma cells after radiotherapy.

Materials and methods: The gadolinium-enhanced T1-weighted and T2-weighted magnetic resonance imaging volumes were segmented and used to calculate the velocity of radial expansion (v) and the net rates of proliferation (rho) and invasion/dispersal (D) for each patient according to the bio-mathematical model.

Results: The ranges of the values of v, D and rho show that glioblastomas, although clustering at the high end of rates, vary widely one from the other. The effects of X-ray therapy varied from patient to patient. About half survived as predicted without treatment, indicating radio-resistance of these tumours. The other half survived up to about twice as long as predicted without treatment and could have had a corresponding loss of glioma cells, indicating some degree of radio-sensitivity. These results approach the historical estimates that radiotherapy can double survival of the average patient with a glioblastoma.

Conclusions: These cases are among the first for which values of v, D and rho have been calculated for glioblastomas. The results constitute a 'proof of principle' by combining our bio-mathematical model for glioma growth and invasion with pre-treatment imaging observations to provide a new tool showing that individual glioblastomas may be identified as having been radio-resistant or radio-sensitive.

MeSH terms

  • Adult
  • Aged
  • Brain Neoplasms / mortality
  • Brain Neoplasms / pathology
  • Brain Neoplasms / radiotherapy*
  • Contrast Media
  • Female
  • Glioblastoma / mortality
  • Glioblastoma / pathology
  • Glioblastoma / radiotherapy*
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Survival Rate
  • Tumor Burden

Substances

  • Contrast Media