Mapping high-grade glioma immune infiltration to 5-ALA fluorescence levels: TCGA data computation, classical histology, and digital image analysis

Combined Fluorescence-Guided Surgery with 5-Aminolevulinic Acid and Fluorescein in Glioblastoma: Technical Description and Report of 100 Cases

BACKGROUND

Fluorescence-guided resection (FGR) of glioblastomas has been previously explored with the use of 5-amivelulinic acid (5-ALA) and sodium fluoresceine (SF), allowing us to maximize the extent of resection (EoR). In this study, we highlight the most relevant concerns regarding this technique and present the methods and results from the experience of our center.

METHODS

A case series of 100 patients operated on in AOU Città della Salute e della Scienza in Turin with a histological diagnosis of glioblastoma (grade IV, according to WHO 2021) was retrospectively analyzed. Both 5-ALA and SF were administered and intraoperatively assessed with an optical microscope.

RESULTS

5-ALA is the only approved drug for FGR in glioblastoma, reporting an increased EoR. Nevertheless, SF can be positively used in addition to 5-ALA to reduce the risk of false positives without increasing the rate of adverse effects. In our experience, SF was used to guide the initial phase of resection while 5-ALA was used to visualize tumor spots within the surgical cavity. In 96% of cases, gross total resection was achieved, with supra-maximal resection in 11% of cases.

CONCLUSIONS

Combined FGR using 5-ALA and SF seems to be a promising method of increasing the extent of resection and to improving the prognosis in glioblastoma patients.

Fluorescence and immune-cell infiltration of nonneoplastic, postbrachytherapy brain tissue in 5-ALA-guided resection of recurrent anaplastic meningioma: illustrative case

BACKGROUND

5-Aminolevulinic acid (5-ALA) fluorescence-guided surgery is a well-established technique for resecting high-grade gliomas. However, its application in meningiomas, especially those previously treated with radiation therapy, remains under investigation.

OBSERVATIONS

A 48-year-old female with recurrent anaplastic meningioma, World Health Organization grade 3, underwent a right-sided craniotomy using off-label 5-ALA as a surgical adjunct. The patient had previously undergone brachytherapy seed implantation (20 × cesium 131) for tumor management. During the surgery, a large fluorescent tumor mass adjacent to the brachytherapy-treated area was resected, and the prior brachytherapy seeds were removed. Interestingly, the surrounding brain tissue in the irradiated area showed robust 5-ALA fluorescence. Pathological examination confirmed that the fluorescent brain tissue was nonneoplastic and associated with lymphocyte and macrophage infiltration.

LESSONS

This case report presents unique 5-ALA fluorescence in nonneoplastic tissue following brachytherapy, which was found during the resection of recurrent anaplastic meningioma. This phenomenon may reflect an intricate interplay among radiation therapy, immune cells, the tumor microenvironment, and 5-ALA metabolism. Given that false-positive findings in fluorescence-guided surgery can lead to unnecessary tissue resection and increased surgical morbidity, further research is warranted to elucidate the mechanisms underlying this phenomenon and its implications for meningioma surgery.

Clinical Application of the Association between Genetic Alteration and Intraoperative Fluorescence Activity of 5-Aminolevulinic Acid during the Resection of Brain Metastasis of Lung Adenocarcinoma

The primary objective of this study was to investigate the association of certain genetic alterations and intraoperative fluorescent activity of 5-aminolevulinic acid (ALA) in brain metastasis (BM) of lung adenocarcinoma. A retrospective cohort study was conducted among 72 patients who underwent surgical resection of BM of lung adenocarcinoma at our institute for five years. Cancer cell infiltration was estimated by the intraoperative fluorescent activity of 5-ALA, and genetic alterations were analyzed by next-generation sequencing (NGS). The sensitivity and specificity for detecting cancer cell infiltration using 5-ALA were 87.5% and 96.4%, respectively. Genes associated with cell cycle regulation (p = 0.003) and cell proliferation (p = 0.044) were significantly associated with positive fluorescence activity of 5-ALA in the adjacent brain tissue. Genetic alterations in cell cycle regulation and cell proliferation were also associated with shorter recurrence-free survival (p = 0.013 and p = 0.042, respectively) and overall survival (p = 0.026 and p = 0.042, respectively) in the multivariate analysis. The results suggest that genetic alterations in cell cycle regulation and cell proliferation are associated with positive fluorescence activity of 5-ALA in the adjacent infiltrative brain tissue and influence the clinical outcome of BM of lung adenocarcinoma.