gms | German Medical Science

Objective: In case of tumor recurrence of glioblastoma (rGBM), complete re-resection of the tumor plays an important role in prolonging survival. Differentiating tumor tissue from surrounding brain tissue can be challenging. In first resection 5’-aminolaevulinic acid (5’-ALA), which is administered a few hours preoperatively, leads to tumor-fluorescence during surgery and therefore enhances resection radicality. With this study, we intended to investigate if 5’-ALA is equally helpful as a surgical tool in the setting of rGBM.

Method: We performed a retrospective analysis of our prospectively collected patient database and identified 39 patients with histologically proven rGBM, who underwent repeat resection between October 2007 and May 2011. In all patients, complete resections according to MRI-criteria were planned. Every patient received 5’-ALA (20 mg/kg bodyweight) prior to surgery and had pre- and early postoperative MRI to perform volumetric analyses of tumor resection.

Results: Median patient age was 55 years, median KPS was 90 and median tumorvolume was 13.42 cm³. Complete tumor resection was achieved in 31 patients (79%), 8 (20.5%) had subtotal resection. Among the latter 3 patients had removal of >90% and 2 more patients had removal of >80% of the initial tumor volume. Intraoperatively, tumor-like tissue fluorescence (bright or vague) could not be visualized in 15 patients (37.5%). Extent of resection achieved did not significantly differ between patients with or without visible fluorescence (p= 0.65). Interestingly survival since repeat surgery in patients who showed fluorescence was shorter than in patients without florescence (9.6 months vs 12.7 months, p=0.41)

Conclusions: 5-’ALA is a useful surgical tool also in surgery of rGBM, although not all tumors exhibited fluorescence. Therefore, we propose that other means of resection control should be combined with of 5’-ALA in rGBM (e.g. iMRI), if available.