GCT-57. ARE MELATONIN LEVELS A RELIABLE MARKER FOR INTRACRANIAL GERM CELL TUMORS POST TREATMENT DEFICIENCY?

BACKGROUND: Pineal is the melatonin-producing gland, with this hormone importantly acting as a central and peripheral chronobiotic, antioxidant and in energy metabolism. The urinary dosage of 6-sulfatoxymelatonin (aMT6s), a melatonin metabolite, is an indirect marker to estimate the total melatonin nocturnal production, ranging in clinically normal individuals from 10–50 micrograms(ug). The purpose of this study was to evaluate aMT6s in patients with diagnosis of intracranial germ cell tumors (iGCT) treated at IOP/GRAACC/UNIFESP. METHODS: After an interview to collect data about therapies employed and medications, night urine samples (from 8:00pm to first void in the morning) were collected and analyzed by ELISA. RESULTS: Twenty patients between 5–42 years old (mean 20.9 years), all male, were analyzed. Thirteen patients had diagnosis of Germinoma, 1 with Imature Teratoma, 5 NGGCT and 2 Mature Teratoma. The first site was pineal (N=15) and bifocal (N=5). The treatment was surgery/biopsy/2º look surgery in 17 patients associated with chemotherapy/ radiotherapy, except in 2 (pure teratoma-surgery only) and 1 (chemo only). Three patients had diagnosis by tumor markers treated with chemo only (N=1) and chemotherapy/radiotherapy (N=2). The levels of aMT6s were between 0.2–3.2ug in all participants, except in one (14.8ug-biopsy, chemo and RT). CONCLUSION: aMT6s levels found in most patients are below the expected for the general population suggesting that this is an appropriate marker for pineal tumors with melatonin deficiency. It may contribute to support future studies in this area and adoption of follow-up protocols, with eventual hormone supplementation and consequently improved quality of life.