LEIOMYOSARCOMA AND LIPOSARCOMA IN YOUNG PATIENTS: THE NATIONAL NETSARC+ NETWORK EXPERIENCE

BackgroundLeiomyosarcoma (LMS) and liposarcoma (LPS) are ultra-rare sarcomas in pediatric (0-18 years) young adult (19-30) populations. We aimed to analyze their clinical characteristics at these ages determine whether they should be considered with the same therapeutic strategy both populations.MethodsNational retrospective multicenter study of all patients (0-30 included sarcoma database “ConticaBase”, treated for LMS or LPS between 2010 2019 via national NETSARC+ network, available pathology/biology review.FindingsA total 218 were identified, 34 children (nine LMS, 25 LPS) 184 adults (58 126 LPS). Myxoid/Round Cell (M/RC-LPS) was most frequent subtype (72%). All had localized LPS, versus 52/58 116/126 respectively adults. Clinical presentation subtypes comparable populations, except a preferential limb location children. The mainly based on primary surgery (9/9 children, adults) (respectively 25/25 122/126), exclusively adjuvant radiotherapy systemic treatment. With median follow-up 62.4 months (range, 2.5-146), 5-year overall survival 83% [95% CI, 58-100] 73% [61–88] 100% [100-100] vs 92% [87–99] M/RC-LPS 25% [5-100] 60% [29-100] pleomorphic LPS.InterpretationLMS appear display behavior authors propose that groups.