Important information on Gliolan (5-aminolevulinic acid, 5-ALA): What to do in case of delayed surgery and information on fluorescence in non high-grade glioma.

Occasionally, delays and postponement of surgery may occur despite 5-ALA having been administered. It is basically unknown for how long useful fluorescence persists in tumour cells beyond the defined window of lucid contrast. If the surgery is delayed by more than 12 hours, surgery should be re-scheduled for the next day or later. Another dose of this medicine can be taken 2 – 4 hours before anaesthesia.           

Re-administration of 5-ALA on the same day should be avoided as no data are available on the safety of a repeated dose of 5-ALA or the specificity of fluorescence with repeat same day administration.

Neurosurgeons are reminded that fluorescence can be encountered in metastasis, inflammation, CNS infections (fungal or bacterial abscess), lymphoma, reactive changes or necrotic tissue, which does not indicate the presence of glioma cells. On the other hand, non-fluorescing tissue in the surgical field does not rule out the presence of tumour in the low density infiltration zone of patients with glioma.