gms | German Medical Science

Objective: The extent of resection is one the most important prognostic factors for survival of glioblastoma (GBM) patients. Due to its highly infiltrating growth the tumor exceeds the visible resection borders defined by contrast enhancement on MRI. The adjacent hyperintense tissue seen in FLAIR MRI-sequence is considered to include the tumor infiltration zone. The postoperative dynamics of FLAIR were described as an early marker of tumor recurrence. Long-term survivors (LTS) make up a small group of GBM patients with a survival time of more than 3 years. Prognostic factors of long survival are not fully understood. In this study, we addressed the predictive role of the FLAIR-hypertintensity for long survival with GBM.

Methods: Theconsecutive patients were treated with gross total resection and Stupp protocol at our department from 2008 to 2017. LTS was defined as overall survival (OS) >36 months, long PFS as tumor-free state >12 months, while short PFS was set to <6 months. We performed a volumetric analysis of MRI datasets preoperatively, early postoperatively and at first radiologic follow-up after 3-6 months.

Results: We identified 12 LTS (mean 56 years). The mean PFS was 43.3 months. The mean tumor volume was 35.0 cm3 and preoperative FLAIR was 67.7 cm3. There was only a slight not-significant FLAIR reduction on early postoperative MRI. A significant decrease of FLAIR-hyperintensity (57.2 cm3, p=0.04) was seen at first follow-up MRI. Within the LTS cohort, PFS significantly correlated with preoperative FLAIR/tumor ratio (r=0.762, p=0.004). A cohort of 11 patients (mean age 60.4 years) with short PFS was compared to the patients with long PFS (3.9 vs. 43.3 months, p=0.02). There was a significant difference in FLAIR dynamics between the preoperative MRI and the first radiologic follow-up (long PFS 74.4 cm3 vs. short PFS 15.7 cm3, p=0.01). There was a tendency towards larger preoperative FLAIR-hyperintensity volume in patients with longer PFS (80.2cm3 vs. 49.7 cm3, p=0.67) as well as higher preoperative FLAIR/tumor ratio (3.5 vs. 2.2, p=1.59).

Conclusion: Preoperative FLAIR/tumor ratio was significantly associated with prolonged PFS in LTS group, which was not seen in a group with a short PFS. Patients with prolonged PFS had higher reduction of FLAIR-hyperintensity at first radiologic follow-up. Our results suggest a potential role of FLAIR for prognostic evaluation of GBM patients, which has to be confirmed in a prospective study.