gms | German Medical Science

Objective: Fluorescence guided surgery with 5-aminolevulinic acid (5-ALA) for adult malignant glioma was tested in a phase III trial in which an increase in the rate of gross total resection as well as an improvement of the progression free survival were observed. The technique has since been established as standard in surgery of adult primary brain tumors. To our knowledge, only one case report of fluorescence guided surgery for medulloblastoma in a child has been published. Here, we report a series of pediatric brain tumors resected after administration of 5-ALA.

Methods: 14 patients (9 f, 5 m) with a mean age of 9 years (range 4–17 years) received 5-ALA according to the published protocol, i.e. 20 mg/kg bodyweight 5-ALA diluted in water and orally administered 3-5 hours prior to surgery. Patients with known hepatic, renal or hematological pathology were not eligible. Operations were performed under white light using an operation microscope (OPMI^® Pentero^™, Carl Zeiss GmbH, Germany) and the neurosurgeon repeatedly switched into fluorescence mode to inspect the resection cavity and adjacent tissue for red fluorescence. Blood samples were taken before and after surgery and analyzed for hematological, renal and hepatic parameters. Patients were examined by pediatricians for signs of adverse drug reaction.

Results: Neuropathological analysis revealed pilocytic astrocytoma WHO grade I (n=7), classical medulloblastoma WHO grade IV (n=4), anaplastic astrocytoma WHO grade III (n=1), anaplastic ependymoma WHO grade III (n=1) and ganglioglioma WHO grade I (n=1). 12 tumors were located in the posterior fossa. Positive red fluorescence of tumor tissue was observed in 3 cases (medulloblastoma n=1, anaplastic astrocytoma n=1 and ganglioglioma n=1). Significant increases were observed for alanine aminotransferase (14.9 U/l vs. 37.7 U/l, p<0.0001) and gamma glutamyl transpeptidase (12.7 U/l vs. 39.3 U/l, p<0.0001) when comparing samples taken preoperatively versus 7 days after surgery. Renal and hematological parameters remained stable. Clinically, no adverse reactions, such as erythema, were evident.

Conclusions: Positive red fluorescence of tumor tissue was observed in none of the pilocytic astrocytomas and in only one case of medulloblastoma. Thus, according to our data the value of this technique appears questionable in the treatment of the most common brain tumor entities in children. Adverse reactions observed in children were similar to those reported for adults. Larger series are needed to validate these observations.