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.