Perfusion MRI-based differentiation between early tumor progression and pseudoprogression in glioblastoma and its use in clinical practice

Background. Early treatment effects in patients with glioblastoma are frequently discussed during multidisciplinary team meetings (MDTM), after which a decision regarding (dis)continuation of tumor-targeted treatment is made. This study examined whether a separate and systematic evaluation of perfusion MRI (pMRI) could impact such treatment decisions in the early stage. Methods. This retrospective observational study evaluated the diagnostic accuracy for detecting early tumor progression of 4 different approaches including conventional MRI, pMRI with Arterial Spin Labeling (ASL), and/or Dynamic Susceptibility Contrast (DSC) MRI, and compared those to the MDTM evaluation in clinical practice. Results. Sixty-five glioblastoma patients with clinical and radiological data until 9 months after irradiation were included. For all approaches, the sensitivity for detecting early true disease progression was poor to moderate (32%–62%). Area under the curve values were comparable (range 0.63–0.74), but highest for the MDTM evaluation (0.74). In the cases of inconclusive MDTM (26%), systematic pMRI evaluation showed a higher sensitivity compared to conventional MRI (respectively, 36% vs 0%), while the specificity was 100% for all MRI approaches. Multivariable regression analysis showed that a lower KPS score (OR = 0.84 [95% CI: 0.77–0.91]) and pMRI indicative of tumor progression (OR = 0.09 [95% CI: 0.02–0.52]) were independently associated with concluding tumor progression at the MDTM. Conclusion. MDTM assessment in daily clinical practice has a higher diagnostic accuracy in distinguishing early tumor progression from pseudoprogression compared to a separate, systematic evaluation of pMRI. Systematic evaluation of pMRI might be helpful if the clinical MDTM assessment is uncertain.