102P The loss of function of neurofibromin and afadin -6 in neurofibromatosis type-1 may disrupt the endothelial cell-cell adhesion in neurofibromatosis type-1

Background: Young adults aged 18-49 with sarcoma typically have a distinct distribution of sarcoma subtypes and experience different outcomes compared to both children and adolescents, as well as older patients.This study aims to compare the features of early-onset sarcomas (EOS) with late-onset sarcomas (LOS), providing insights into age-related differences in sarcoma presentation and management.Methods: Prospective data from two tertiary hospitals, encompassing 2018 to 2024, were utilized.The study assessed patients diagnosed with sarcomas according to the International Classification of Diseases 10th revision (ICD-10).Early-onset cancer, defined as cases diagnosed in adults between 18 and 49 years.Data extraction was automated, utilizing big data sources in order to obtain information related to ICD codes, demographics, medical history, germline and somatic tests. Results:We analyzed 517 individuals, with 265 (51.26%) aged 18e49 years and 252 (48.74%) aged 50 years or older.Among young adults, 33.58% were diagnosed with metastatic disease at the time of diagnosis, compared to 32.54% in the older cohort (p<0.001).During the analysis period, 28.68% of EOS patients were deceased, compared to 36.11% in the LOS group (p<0.001).In terms of histology, 31.32% of EOS were bone sarcomas, 64.53% were soft-tissue sarcomas, and 4.15% were GISTs.Conversely, 4.25% of LOS were bone sarcomas, 68.65% were soft-tissue sarcomas, and 21.83% were GISTs.Somatic testing was conducted in 8.68% of EOS patients and 7.94% of LOS patients.Germline testing was performed in 7% of EOS patients compared to 12% of LOS patients.Among the young patients, 30% had pathogenic variants identified through germline testing, with mutations in the NBN, APC, BRCA1, CEP57, ERCC3, and PDGFRA genes.Conclusions: This study highlights age-related differences in sarcoma subtypes and outcomes between young adults and older patients, with young adults exhibiting a higher rate of metastatic disease but lower mortality.Although genetic testing was performed in a limited number of cases, it revealed significant pathogenic variants.