Epidemiology and treatment outcomes of bone and soft tissue sarcoma in pediatric and adolescent and young adult patients in Japan: data from population-based National Cancer Registry 2016-2019.

This Japanese population-based retrospective study using National Cancer Registry data (2016-2019) revealed age-specific disparities in treatment and outcomes of bone and soft tissue sarcomas in patients under 40 years. A total of 1,209 bone sarcoma (BS) and 3,096 soft tissue sarcoma (STS) cases were analyzed for demographics, treatment modalities, survival rates, and prognostic factors. Osteosarcoma (53%) and Ewing sarcoma (15%) were the most common BS subtypes. Pediatric patients presented more frequently with metastases and received more chemotherapy, while surgery was performed in 80% of BS cases. For STS, fibrosarcoma (19%) and rhabdomyosarcoma (13%) predominated. AYA (adolescent and young adult) patients underwent more surgeries, whereas pediatric patients received more chemotherapy/radiotherapy. Three-year overall survival rates were 67% for BS and 79% for STS. Prognosis was significantly influenced by disease extent and surgical intervention. Age was an adverse prognostic factor for STS but not for BS. This first comprehensive Japanese population-based study demonstrates treatment disparities across age groups in sarcoma care. We revealed that pediatric and AYA sarcoma care in Japan shows clear age-related disparities.