gms | German Medical Science

Objective: Glioblastomas (GBM) are characterized by a high infiltration rate of the surrounding brain tissue making a complete resection difficult. Nevertheless, the extent of resection correlates with progression free survival (PFS) and overall survival. T1-weithed gadolinium-enhanced (T1-Gd) magnetic resonance imaging (MRI) is used for tumor margin definition and intraoperative guidance of gross total resection (GTR). However, the infiltration zone exceeds the tumor margin as defined in T1-Gd MRI. The aim of this study was to assess the role of persisting FLAIR (fluid attenuated inversion recovery)-hyperintensity in MRI after GTR for detection of residual tumor and prediction of recurrence localization.

Methods: We performed a retrospective analysis of patients with histologically verified GBM and GTR as defined by early postoperative T1-Gd MRI. All patients were treated according to Stupp protocol and received MRI scan in 3 month intervals. The FLAIR-hyperintensity and T1-Gd-enhancement were analyzed on the preoperative, early postoperative and 3 month follow-up MRI. The localization of persisting FLAIR-hyperintensity was correlated with the localization of tumor recurrence. The time from diagnosis to first tumor recurrence was documented.

Results: A total of 43 patients met the inclusion criteria. FLAIR-hyperintensity was visible in all patients on early MRI after GTR. Mean follow- up was 11.85 months (range 3-77). In 86% (37/43) persisting FLAIR-hyperintensity was seen on 3 month follow-up MRI. In 13.5% (5/37) of these patients an increasing FLAIR-hyperintensity and new gadolinium-enhancement indicative of early recurrence was diagnosed on 3 month follow-up MRI. In 81.1% (30/37), recurrence occurred later and 5.4% (2/37) had no recurrence. In 78% (25/32) the recurrent tumor was located within the area of FLAIR-hyperintensity. In 14% (5/37) a distant recurrence occurred. The presence of residual FLAIR-hyperintensity at 3 month follow-up MRI after GTR was significantly correlated with tumor recurrence localization (linear regression, p<0.0001). The mean PFS in the patients without persisting FLAIR-hyperintensity was 20.6 months (range 8-41) compared to 9.9 months (range 4-77) with persisting FLAIR-hyperintensity.

Conclusion: Persisting FLAIR-hyperintensity seen on 3 month follow-up MRI after GBM GTR predicts tumor recurrence and its localization. The consideration of FLAIR additional to T1-Gd MRI for intraoperative guidance of GBM resection might increase the extent of resection.