Background: Compared to young children or older adults, the prognoses of adolescent and young adult (AYA) patients with cancer, i.e., those aged from 15 to 39 years, have not improved. In this study, we focused on soft tissue sarcoma (STS) in AYA patients and aimed to determine whether there is a correlation between the AYA age group and overall poor cancer survival in STS. We further aimed to determine which histologic subtypes are more common in AYA patients and investigate the cause of poor outcomes in this group.
Methods: The medical records of 5853 Japanese patients diagnosed with STS between 2006 and 2013 were accessed from the Bone and Soft Tissue Tumor registry (BSTT). We analyzed and compared the epidemiological features of AYA patients with those of other age groups. The cancer survival rates were calculated using the Kaplan-Meier method. Cox proportional hazards models were used to analyze the prognostic factors for cancer survival. The primary endpoint for prognosis was the occurrence of tumor-related death.
Results: On multivariate analysis, age was not a prognostic factor for poor cancer survival among these patients. Compared to the same categories in other age groups, the proportions of myxoid/round cell liposarcomas, synovial sarcomas, malignant peripheral nerve sheath tumors (MPNST), primitive neuroectodermal tumor, and rhabdomyosarcoma in AYA patients were the highest, but none of the categories were significantly more prevalent in AYA patients. The cancer survival rates of AYA patients with MPNST were poorer than those of the other age groups; however, AYA age was not a prognostic factor on multivariate analysis in MPNST patients.
Conclusions: Our study is the first to investigate STS in AYA patients using the nationwide BSTT registry. Our findings demonstrate that AYA age is not a prognostic factor for poor cancer survival among those with STS in Japan.