Abstract
BACKGROUND: Five-aminolevulinic acid (5-ALA) is used for fluorescence-guided resections of malignant glioma at a dose of 20 mg/kg;yet, it is unknown whether lower doses may also provide efficacy. OBJECTIVE: To perform a double-blinded randomized study comparing 3 different doses of 5-ALA. METHODS: Twenty-one patients with suspected malignant glioma were randomly assigned to 0.2, 2, or 20 mg/kg 5-ALA. Investigators were unaware of dose. Intraoperatively, regions of interest were first defined in tumor core, margin, and adjacent white matter under white light. Under violet-blue illumination, the surgeon's impression of fluorescence was recorded per region, followed by spectrometry and biopsy. Plasma was collected after administration and analyzed for 5-ALA and protoporphyrin IX (PPIX) content. RESULTS: The positive predictive value of fluorescence was 100%. Visual and spectrometric fluorescence assessment showed 20 mg/kg to elicit the strongest fluorescence in tumor core and margins, which correlated with cell density. Spectrometric and visual fluorescence correlated significantly. A 10-fold increase in 5-ALA dose (2-20 mg/kg) resulted in a 4fold increase of fluorescence contrast between marginal tumor and adjacent brain. tmax for 5-ALA was 0.94 h for 20mg/kg (0.2 kg: 0.50 h, 2 mg/kg: 0.61 h). Integrated PPIX plasma levels were 255.8 and 779.9 mcg* h/l (2 vs 20 mg/kg). Peak plasma concentrations were observed at 1.89 +/- 0.71 and 7.83 +/- 0.68 h (2 vs 20 mg/kg;average +/- Standard Error of Mean [SEM]). CONCLUSION: The highest visible and measurable fluorescence was yielded by 20 mg/kg. No fluorescence was elicited at 0.2 mg/kg. Increasing 5-ALA doses did not result in proportional increases in tissue fluorescence or PPIX accumulation in plasma, indicating that doses higher than 20 mg/kg will not elicit useful increases in fluorescence.
Dokumententyp: | Zeitschriftenartikel |
---|---|
Fakultät: | Medizin |
Themengebiete: | 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit |
ISSN: | 0148-396X |
Sprache: | Englisch |
Dokumenten ID: | 51238 |
Datum der Veröffentlichung auf Open Access LMU: | 14. Jun. 2018, 09:45 |
Letzte Änderungen: | 04. Nov. 2020, 13:29 |