Abstract 1181: Associations of socioeconomic status and race/ethnicity with metastasis at sarcoma diagnosis
Authors: Diessner Brandon J. , Spector Logan G. , Poynter Jenny N. 
Published: September 2020

Background: Sarcomas comprise a group rare and heterogeneous neoplasms. As sarcomas have few early recognizable signs, they often have an extended delay between symptom onset and diagnosis. Approximately 10% - 30% of sarcoma cases present with metastasis at diagnosis. However, the extent to which a delayed diagnosis increases the likelihood of presenting with metastasis remains unclear. To expand this under-researched area of study, we sought to determine whether socioeconomic status (SES) or race/ethnicity were independently associated with metastasis at diagnosis of sarcoma by individual subtype.

Methods: The influence of small-area SES and race/ethnicity on metastasis at diagnosis of sarcoma across all ages was evaluated using data from the SEER program (years of diagnosis: 2001 – 2015). Small-area SES was evaluated from a composite index measured at the census-tract level. Odds ratios (OR) for presenting with metastasis and 95% confidence intervals (CI) were estimated from logistic regression models that included SES as an ordinal variable, race/ethnicity, age, sex and year of diagnosis. Analyses were stratified by age groups (pediatric; &lt; 20 years, adult: 20 – 65 years, older adult: 65 + years) and reported for any subtype with more than 100 metastatic cases within each age group category. A secondary analysis of adult cases evaluated the influence of insurance status (uninsured, Medicaid insured, privately insured) on metastasis using logistic regression, adjusted for small-area SES, race/ethnicity, sex, age, and year; this analysis was restricted to the years of available data, 2007 – 2015.

Results: A total of 55,635 first primary sarcoma cases were identified. A higher SES was associated with a lower odds of metastasis for pediatric osteosarcoma (ordinal OR: 0.90, 95% CI: 0.85, 0.99; p-trend: 0.02), liposarcoma in adults (ordinal OR: 0.85, 95% CI: 0.78, 0.94; p-trend: 0.001) and unclassified sarcomas in adults (ordinal OR: 0.91, 95% CI: 0.84, 0.98; p-trend: 0.01) and older adults (ordinal OR: 0.91, 95% CI: 0.83, 0.99; p-trend: 0.03); the odds of metastasis in the remaining subtypes evaluated were not associated with SES. We also observed the odds of metastasis to be higher in minority populations compared to non-Hispanic (NH)-white cases for several subtypes, including leiomyosarcoma in NH-black (OR: 1.80, 95% CI: 1.51, 2.14), Asian pacific islander and American Indian or Alaskan native (API/AIAN) (OR: 1.45, 95% CI: 1.17, 1.79), and Hispanic (OR: 1.32, 95% CI: 1.10, 1.57) adult cases, as well as Ewing sarcoma of soft tissue in Hispanic adult cases (OR: 1.81, 95% CI: 1.07, 1.34). Having Medicaid or no insurance was a strong predictor of presenting with metastasis for all subtypes evaluated, except Ewing sarcoma of bone (significant ORs ranged from 1.38 to 2.27), and attenuated the associations with SES. The increased odds of metastasis among NH-Black cases with leiomyosarcoma and unclassified sarcomas, however, remained statistically significant. (Leiomyosarcoma OR: 1.88, 95% CI: 1.52, 2.33; unclassified sarcomas OR: 1.62, 95% CI: 1.11, 2.35).

Conclusion: Small-area SES was not associated with metastasis at diagnosis of most sarcomas. However, based on our analysis of insurance status, delayed access to care may still be an important predictor advanced stage. Biological factors may also play a role in the racial disparities for sarcoma stage observed in adults.

Citation Format: Brandon J. Diessner, Logan G. Spector, Jenny N. Poynter. Associations of socioeconomic status and race/ethnicity with metastasis at sarcoma diagnosis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1181.