1 | INTRODUCTION
Osteogenic sarcoma (OGS) is the most prevalent primary bone cancer, accounting for almost two-thirds of all bone malignancies and is the most common primary bone cancer in children and adolescents.1,2 Ewing sarcoma (EWS) is the second most prevalent bone cancer in all ages.3 Both tumors are common and cause considerable morbidity and mortality in the adolescent and young adult population (AYA; ages of 15 to 39 years).4
The location of cancer therapy or locus of care (LOC: pediatric versus adult centers) may impact outcomes in AYA with cancer. Variations in care according to LOC, including type and intensity of therapy, access to clinical trials, and treatment team experience may result in differences in survival outcomes.5.6
Differences in outcomes according to LOC have been studied in AYA with leukemia, lymphoma, brain tumors, and soft tissue sarcomas.5,7-15However, few studies have compared treatment differences between pediatric and adult centers and explored the impact of LOC on outcomes in bone tumors.12,13,16Differences in treatment intensity and/or time to local therapy are among the possible reasons for outcome disparities in AYA bone tumors.12,13,16 The existence of such LOC-based disparities would inform policy and may improve bone tumor outcomes. However, prior studies have been limited by small patient numbers and inconsistent results.
It is a common assumption that prolonged diagnostic interval length (DIL) for cancer has a negative influence on survival because of a risk for more advanced stage disease at diagnosis.17 Delays in the diagnosis and initiation of treatment of bone cancers are common, as their symptoms are often vague and misleading or may be misattributed to other pathologies.18 However, most prior studies have not shown any association between prolonged DIL and survival in OGS or EWS.19-21
We used a population-based provincial cancer registry, to explore outcome disparities among AYA with OGS or EWS treated at pediatric versus adult cancer centers, and to examine the impact of DIL on survival.