Synovial sarcoma disease characteristics and primary tumor sites differ between patient age groups: a report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

Abstract

Background Older age is associated with worse outcome in synovial sarcoma (SS) patients. Differences in disease presentation among distinct age groups, however, are currently unknown. Methods SS patients < 21 years registered in consecutive CWS trials over the period of 1981–2018 were evaluated. Characteristics were analyzed according to age groups using the Fisher’s exact test. Results The study population included 432 SS patients. Disease characteristics differed according to age groups of children (0–12 years, n = 176), adolescents (13–16 years, n = 178), and young adults (17–21 years, n = 78). The proportion of invasive tumors (T2) was significantly higher in older patients: children 33%, adolescents 39% and young adults 54%, p = 0.009805. Similarly, the proportion of tumors > 10 cm was higher (13%, 21%, 31%; p = 0.005657) whereas conversely, the proportion of small tumors < 3 cm was lower in older patients (29%, 24%, 6%; p = 0.000104). The presence of metastases at first diagnosis was also highest in older patients (6%, 10%, 21%, p = 0.000963). Notably, the proportion of thigh tumors was higher in older patients (p = 0.04173), whereas the proportion of head–neck tumors was lower in older patients (p = 0.08896). Conclusions The rates of large, invasive tumors and the presence of metastases are significantly associated with older patient age. Localization to the thigh is more frequent in older patients. Discussion The causes for these variations require further exploration.