Feasibility of fluorescence-guided resection of recurrent gliomas using five-aminolevulinic acid: retrospective analysis of surgical and neurological outcome in 58 patients.

Five-aminolevulinic-acid (5-ALA) is known for its benefits in surgery of primary gliomas, but has only been cautiously used in recurrent gliomas dreading over-resection, insufficient or false-positive fluorescence in adjuvantly treated tumors. We evaluated intraoperative fluorescence based on tumor pathology, pretreatment as well as surgical and neurological outcome in patients with recurrent gliomas. Patients who underwent fluorescence-guided surgery for recurrent gliomas between 6/2010 and 2/2014 at our institution were retrospectively selected. Degree of surgical resection, neurological status, pathology results, intraoperative fluorescence and follow up status were analyzed. Patients who underwent repeat surgery without 5-ALA were selected as controls. 58 patients with high grade gliomas (°III and °IV) were included. 10 of 63 tumors (15.9 %) failed to fluoresce intraoperatively of which nine (90 %) had been adjuvantly treated prior to recurrence, as were 46 of the 53 fluorescing tumors (86.8 %). Non-fluorescing tumors were IDH mutated significantly more often (p = 0.005). 30 tumors (47.6 %) were located eloquently. 51 (80.9 %) patients showed no new neurologic deficits postoperatively. 13 patients (20.6 %) showed no signs of recurrence at their latest follow up. Eight patients were lost to follow up. Overall survival was significantly longer in the 5-ALA group (p = 0.025). Fluorescence-guided surgery in recurrent gliomas is safe and allows for a good surgical and neurological outcome in a difficult surgical environment, especially when used in combination with neuronavigation and intraoperative ultrasound to prevent over-resection. Adjuvant therapy did not significantly influence fluorescing properties.