3.2 | Ewing sarcoma
3.2.1 | Demographic, diagnosis,
disease, and treatment variables
As shown in Table 1 ,
patients treated at a pediatric center were more likely to be younger
and have limb involvement than those treated at an adult center.
Clinical trial enrollment was significantly more frequent in pediatric
centers versus adult centers (53% versus 2%, p<0.001). Sex,
DIL, and socioeconomic status did not differ by LOC.
Pediatric centers provided their EWS patients with local therapy (either
surgery only or radiation only or both surgery and radiation) earlier
than adult centers, regardless of the type of local therapy
(Table 3 ). Time to local therapy was not significantly
different between localized and metastatic patients. There was no
statistically significant difference in radiation doses between
pediatric and adult centers.
The most commonly used chemotherapeutic agents were cyclophosphamide,
doxorubicin, ifosfamide and etoposide. The median cumulative doses of
cyclophosphamide, ifosfamide,
etoposide, and the CED were
significantly higher in pediatric center patients compared with adult
center patients.
3.2.2 | Survival outcomes
The median follow-up time was 6.6 years (IQR 1.7 to 14.1 years; range
0.5-25.2 years). None of the variables (including locus of care/age and
primary site) was associated with EFS in localized cohort (Fig.
2A and 2B ). In metastatic cohort, only receiving higher dose of
etoposide was significantly associated with higher EFS rate (5-year EFS
± SE: 25% ± 11% vs 0; 0.0001).
Table 4 demonstrates the results of Cox proportional hazards
survival analyses in both localized and metastatic EWS
cohorts. In univariate analysis of
the localized disease cohort, none of the variables including locus of
care/age and primary tumor location showed statistically significant
association with survival. In multivariable analysis, none of the
variables was significantly associated with EFS (Table 4 ). In
the metastatic cohort multivariable analysis, only the association of
cumulative doses of etoposide showed statistically significant
association with EFS (Table 4 ).