Descriptive epidemiology and outcomes of bone sarcomas in adolescent and young adult patients in Japan.

BACKGROUND

There have been fewer improvements in the clinical outcomes of adolescent and young adult (AYA) patients with cancer than for children and older adults, possibly because fewer studies focus on patients in this age group. The aims of this study were (1) to determine survival rates of bone sarcoma among AYAs in Japan (for comparison with other age groups), and (2) to establish whether belonging to the AYA age group at diagnosis was correlated with poor cancer survival in Japan.

METHODS

A total of 3457 patients diagnosed with bone sarcoma (1930 male and 1527 female) were identified from 63,931 records in the Bone and Soft Tissue Tumor (BSTT) registry, a nationwide Japanese database, from 2006 to 2013. The histologic subtypes of bone sarcoma were osteosarcoma, chondrosarcoma, and Ewing sarcoma. The primary endpoints for prognosis were the occurrence of tumor-related death. We compared the epidemiological features of AYAs with 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.

RESULTS

The majority of AYA had osteosarcoma 631 (56.2%), while 198 (17.6%) had chondrosarcoma. The frequency of bone sarcoma occurrence was highest among AYA patients, who accounted for a marked proportion of patients with each type of sarcoma. With the exception of sarcoma type, AYA patients did not significantly differ from patients in other age groups for any of the investigated clinicopathological parameters. Cancer survival of AYA patients was significantly higher than in the elderly. Univariate and multivariate analyses revealed that AYA status was not a predictor of poor cancer survival. However, older age (≥65 years) was a predictor of poor cancer survival in patients with overall bone sarcoma, osteosarcoma, chondrosarcoma.

CONCLUSION

This epidemiological study is the first to investigate AYA patients with bone sarcoma using the nationwide BSTT Registry. We found that cancer survival of AYA patients was significantly higher than that of the elderly. AYA status was not a predictor of poor cancer survival in Japan.