Results
A total of 9112 pediatric and AYA sarcoma cases were included in this study. The demographic and clinical characteristics of the population are shown in Table 1. The majority of patients were white (75.9%) and non-Hispanic (80.1%) with a median age at diagnosis of 17 years. Primary tumors were most commonly in the extremities (39.1%). Of the total study population, 2932 (32.1%) patients were classified as having low SES, 2084 (22.8%) with middle SES, and 4096 (44.9%) with high SES. The low SES category had a higher proportion of black (26.4%) and Hispanic patients (21.7%) as compared to the high SES category.
There were significant differences in the proportion of patients in each SES category who presented with advanced disease at diagnosis. For patients with low SES, 18.6% had metastatic disease compared to 16.9% in the middle SES category and 15.7% in the high SES (p<0.01). A similar trend was found with increased tumor size, where 53.1% of low SES, 51.6% of middle SES, and 48.4% of high SES patients presented with a tumor that was ≥5cm (p<0.01). The median time to treatment was 5 days (IQR 0-20). Only low SES was associated with an increased median time to treatment of 6 days (IQR 0-22, p<0.01). Most patients received chemotherapy (60.1%), 44.4% received radiation therapy, and 71.8% underwent surgery. More patients in the highest SES category lived in a metropolitan area compared to low SES (90.4% vs. 74.9%, p<0.01) and less than 60 miles from the facility where they received treatment (82.5% vs. 74.4%, p<0.01).
The results of the univariate and multivariate analysis are presented in Table 2. In the univariate analysis, black race was significantly associated with an increased risk of tumor size ≥5cm compared to white (OR=1.36, p<0.01), but not for the presence of metastatic disease. Significant univariate predictors of metastatic disease included low SES (OR=1.23, p<0.01), public or no insurance (OR=1.34, p<0.01 and OR=1.42, p<0.01, respectively). Low and middle SES were significantly associated with an increased risk of a tumor ≥5 cm (OR=1.37, p<0.01 and OR=1.23, p<0.01, respectively) along with both public and no insurance (OR=1.34, p<0.01 and OR=1.92, p<0.01, respectively). Additionally, odds ratios increased with age, with patients in the 13-25-year category 1.96 times more likely to present with metastatic disease and 1.34 times more likely to present with a tumor ≥5 cm.
After accounting for significant variables of interest, our multivariate analysis showed that low SES and public and no insurance remained significant predictors of advanced disease at diagnosis. Compared to high SES, patients with low SES had a 16% increase in the odds of presenting with metastatic disease (p=0.03), and 29% increased odds of presenting with tumor size ≥5cm (p<0.01). Middle SES showed a 17% increase in odds of tumor size ≥5cm compared to high SES (p=0.01), but no difference in metastatic disease (p=0.37). Compared to private insurance, public insurance was associated with metastatic disease (OR= 1.35, p<0.01) and increased tumor size (OR=1.28, p<0.01). Additionally, lack of insurance was associated with increased odds ratios of presenting with metastatic disease (OR=1.32, p=0.02) and larger tumor size (OR=1.67, p<0.01).