Comparing children and adults with synovial sarcoma in the Surveillance, Epidemiology, and End Results program, 1983 to 2005

BACKGROUND: Synovial sarcoma (SS) is a typical soft tissue sarcoma subtype crosswise between the pediatric and the adult age groups. Less satisfactory overall outcome has been recorded in adult series. METHODS: This study compares clinical features and outcomes of SS across the different age groups, by analyzing 1268 cases, 213 children/adolescents (<or=18 years) and 1055 adults, registered in the Surveillance, Epidemiology, and End Results (SEER) 17 database from 1983 to 2005. Cancer-specific survival estimates were compared with univariate and multivariate models. RESULTS: No major differences in stage distribution (localized, regional, and distant stage) were observed comparing the 2 age groups. The estimated 5-year cancer-specific survival was 83% for children/adolescents and 62% for adults (P<.001). Female sex, nonblack race, tumors located in the extremities, localized tumors, and tumors <5 cm in size were associated with better survival. In multivariate analysis, adult patients had significantly higher mortality rates than children after adjusting for other variables. CONCLUSIONS: Children and adults with SS have a similar clinical presentation but a dissimilar outcome, suggesting that factors other than unfavorable clinical features might be involved in the unsatisfactory outcome of adult SS patients. It remains to be ascertained whether this difference is related to biological variables or to historically different treatment approaches adopted in pediatric versus adult patients.