Metastatic Soft Tissue Sarcomas in Adolescents and Young Adults: A Specialist Center Experience

Soft tissue sarcomas (STS) account for 8% of all cancers in adolescents and young adults (AYAs). Metastatic STS contribute significantly to disease-related mortality in this age group; however, data are limited due to under-representation in clinical trials. AYAs aged 18-39 years, diagnosed with metastatic STS between 1990 and 2012, were identified from The Royal Marsden Hospital database. Outcomes of interest were clinical characteristics, treatment patterns, overall survival (OS), and prognostic factors. Overall, 455 patients were included. Median age at diagnosis of metastatic STS was 33 years (interquartile range [IQR] 27-37 years). The most common histological subtypes were leiomyosarcoma (n = 68, 15%), synovial sarcoma (n = 68, 15%), Ewing sarcoma (n = 44, 10%), and rhabdomyosarcoma (n = 35, 8%). Treatments included systemic therapy (n = 395, 87%; median 2 lines [IQR 1-3]; clinical trial n = 93, 22%), radiotherapy (n = 297, 66%), and metastasectomy (n = 191, 43%). Median duration between last chemotherapy regimen and death was 4.6 months (IQR 2-10). Median OS was 19.2 months (95% confidence interval [CI] 15.8-22.2); 5-year OS was 16%. Of common subtypes, patients with rhabdomyosarcoma had the worst OS (8.8 months; 95% CI 7.9-11.4). Adverse prognostic factors included male gender, synchronous metastases, bone or liver metastases, first-line polychemotherapy, and no metastasectomy. Outcomes were variable; patients with supposed chemosensitive subtypes had particularly poor survival. The diverse behavior of STS in AYAs highlights the need for subtype-specific clinical trials.