P14.03.B Glutamate excitotoxicity in brain metastases from lung, breast, and melanoma treated with stereotactic radiosurgery

Abstract Background Brain metastases (BM) are the most frequent neoplasm in central nervous system (CNS) and primary tumors frequently involved melanoma, lung cancer breast cancer. CNS localisation is associated with poor prognosis, stereotactic radiosurgery (SRS) represents a treatment option for patients good performance status. Glutamate (Glu) neurotransmitter which plays facilitating role carcinogenesis progression of malignant tumors, as well excitotoxicity. Glu efflux from brain regulated by scavengers glutamic oxaloacetic transaminase (GOT), glutamate-pyruvate (GPT) lactate dehydrogenase (LDH), aspartate catabolites. seems to be impaired advanced-stage cancers, resulting increased blood levels where exert protective role. Our hypothesis that serum scavengers’ related neuroinvasion response BM may represent potential biomarkers course prognosis. Material Methods Serum (GOT1, GPT LDH), Glu, collected included treated grouped A) group affected or SRS; B) Control-1 cancer, melanoma but without C) Control-2 benign intracranial lesions (meningiomas, acoustic schwannomas) SRS.In metabolites will analyzed before after SRS (at 3, 6, 9 months) while once. Blood help identifying differences malignancy, association disease control, detecting BMs. Exclusion criteria surgical previous radiosurgical BM. This study has received Institutional Ethical Committee approval on 3rd August 2020 (Project NCH04-2020, Clinicaltrials.gov identifier: NCT04785521). Preliminary results Comparison between (n = 32) (n=18) revealed significant difference LDH (271.93 vs 217.56 U/L; p 0.041) (1.86 1.34 mmol/L, 0.022) trend towards significance glutamate (103.43 73.74 µmol/L, 0.07). (n=32) 37) 210.89 < 0.001), 1.24 mmol/L; (16.36 10.22 0.006) (123 103 0.052). Conclusion The present first one addressing scavenger If confirmed, new targets signalling pathway could identified define therapeutic strategies this challenging disease.