Cerebral blood flow changes after radiation therapy identifies pseudoprogression in diffuse intrinsic pontine gliomas.
Calmon R, Puget S, Varlet P, Dangouloff-Ros V, Blauwblomme T, Beccaria K, Grevent D, Sainte-Rose C, Castel D, Debily MA, Dufour C, Bolle S, Dhermain F, Saitovitch A, Zilbovicius M, Brunelle F, Grill J, Boddaert N.
Source : Neuro-oncology
2019 Oct 8
Pmid : 29244086
Methods: Multimodal MRIs of 43 children treated for DIPG were retrospectively selected at 4 timepoints: baseline, after radiotherapy, during true progression, and at the last visit. The patients were divided into 2 groups depending on whether they presented conventional MRI changes that mimicked progression. The apparent diffusion coefficient, arterial spin labeling cerebral blood flow (ASL-CBF), and dynamic susceptibility contrast perfusion relative cerebral blood volume (DSCrCBV) and flow (DSCrCBF) values were recorded for each tumor voxel, avoiding necrotic areas.
Results: After radiotherapy, 19 patients (44%) showed radiological signs that mimicked progression: 16 survived >6 months following so-called pseudoprogression, with a median of 8.9 months and a maximum of 35.6 months. All 43 patients exhibited increased blood volume and flow after radiotherapy, but the 90th percentile of those with signs of pseudoprogression had a greater increase of ASL-CBF (P < 0.001). Survival between the 2 groups did not differ significantly. During true progression, DSCrCBF and DSCrCBV values increased only in patients who had not experienced pseudoprogression.
Conclusions: Pseudoprogression is a frequent phenomenon in DIPG patients. This condition needs to be recognized before considering treatment discontinuation. In this study, the larger increase of the ASL-CBF ratio after radiotherapy accurately distinguished pseudoprogression from true progression.