Survival analysis in patients with glioblastoma multiforme: predictive value of choline-to-N-acetylaspartate index, apparent diffusion coefficient, and relative cerebral blood volume

Abstract

Purpose: To investigate the potential value of pre-external-beam radiation therapy (XRT) choline-to-NAA (N-acetylaspartate) index (CNI), apparent diffusion coefficient (ADC), and relative cerebral blood volume (rCBV) for predicting survival in newly diagnosed patients with glioblastoma multiforme (GBM).

Materials and methods: Twenty-eight patients with GBM were studied using in vivo proton magnetic resonance spectroscopic imaging (1H MRSI) and diffusion- and perfusion-weighted imaging after surgery but prior to XRT. Patients were categorized on the basis of their volumes of morphologic and metabolic abnormalities (volume of CNI > or = 2 and CNI values), normalized ADC (nADC), or rCBV values within the T1 contrast-enhancing and T2 regions. The median survival time was compared.

Results: A significantly shorter median survival time was observed for patients with a large volume of metabolic abnormality than for those with a small abnormality (12.0 and 17.1 months, respectively, P = 0.002). A similar pattern was observed for patients with a low mean nADC value compared to those with high mean nADC value within the T2 region (11.2 and 21.7 months, respectively, P = 0.004). A shorter median survival time was also observed for patients with contrast-enhancing residual disease than for those without the presence of contrast enhancement with marginal significance.

Conclusion: The pre-XRT volume of the metabolic abnormality and the nADC value within the T2 region may be valuable in predicting outcome for patients with GBM.