3.1 | Osteogenic sarcoma
3.1.1 | Demographic, diagnosis, disease, and treatment variables
As demonstrated in Table 1 , patients treated at a pediatric center were statistically significantly younger (15.57 ± 0.85 years vs 17.99 ± 1.50 years, p<0.001) and more likely to have metastases than those treated at an adult center (36.2% vs 16.7%, p=0.01). Clinical trial enrollment was significantly more common in pediatric centers compared to adult centers (55% versus 1%, p<0.001). The distribution of sex, DIL, socioeconomic variables, and bone primary site did not differ between pediatric and adult centers.
There was no difference in the type of local therapy or time to local therapy in pediatric versus adult centers.
The median cumulative doses of methotrexate, doxorubicin, and the CED were all significantly and substantially higher in pediatric centers than adult centers.
3.1.2 | Survival outcomes
The median follow-up time was 8.1 years (Interquartile range [IQR] 2.0 - 17.1 years; range 0.0 -26.7 years). Among patients with localized disease, EFS was the longest in the patients aged 18 or older who received care in adult centers followed by pediatric-center patients and adult-center patients younger than 18 years, respectively (5-year EFS ± SE: 66% ± 7% vs 53% ± 9% vs 43% ± 9%; p=0.04) (Fig. 1A and 1B ). Females had significantly better survival outcome than males (5-year EFS ± SE: 76% ± 7% vs 46% ± 6; p=0.006).Among those with metastatic disease, higher 5-year EFS rates were observed in the patients who received higher doses of doxorubicin (36% ± 15% vs 6% ± 6%; p=0.004), methotrexate (44% ± 17% vs 5% ± 5%; p=0.001), and cisplatin (31% ± 13% vs 7% ± 6%; p=0.03). None of tumor primary site, income quintile, rurality, immigration status, DIL, clinical trial enrollment, or time to local therapy were associated with EFS in localized or metastatic cohorts.
Table 2 shows the results of univariate and multivariable Cox proportional hazards survival analyses in both localized and metastatic OGS cohorts. Multivariable analysis in the localized cohort revealed only the statistically significant association of sex with EFS; (i.e., males had inferior EFS compared to females). In the metastatic cohort, only the association of higher cumulative doses of methotrexate, doxorubicin and cisplatin with better EFS were significant in multivariable analyses.