Social vulnerability and survival in 112,000 adolescents and young adults with cancer: a population-based study in Texas
Introduction
Disparities in cancer survival have been widely reported for adult populations, but little is known about these disparities in the growing population of adolescents and young adults (AYA, aged 15-39 years) diagnosed with cancer.
Methods
We used population-based data from the Texas Cancer Registry (TCR) to identify AYAs diagnosed between January 1, 1995, and December 31, 2016. The TCR provided patients’ census tracts based on their addresses at diagnosis. We assigned each patient a neighborhood-level social vulnerability score and categorized them into quintiles using the Centers for Disease Control and Prevention’s Social Vulnerability Index (SVI). The SVI consists of neighborhood-level measures such as socioeconomic status, language barriers, and housing structures. The association between SVI quintiles and all-cause mortality was examined using multivariable Cox proportional hazards regression models, adjusting for race/ethnicity, age, sex, diagnosis year, cancer type, and stage at diagnosis.
Results
Of 112,138 AYAs, most were women (61.16%) and non-Hispanic White (54.23%). Neighborhood vulnerability was associated with all-cause mortality, and the association increased as SVI vulnerability increased. For example, AYAs in the most vulnerable quintile had almost twice the risk [hazard ratio (HR) = 1.95; 95% confidence interval (CI) = 1.88, 2.02] of all-cause mortality compared to those in the least vulnerable SVI quintile. AYAs in the third quintile had 1.42 (95% CI = 1.36, 1.48) times the risk of all-cause mortality compared to those in the least vulnerable SVI quintile. After adjusting for covariables, AYAs in the most vulnerable quintile had an elevated risk (aHR = 1.47; 95% CI = 1.40, 1.53) of all-cause mortality compared to those in the least vulnerable SVI quintile. Similarly, AYAs in the third quintile had 1.26 (95% CI = 1.20, 1.32) times the risk of all-cause mortality compared to those in the least vulnerable SVI quintile. This pattern persisted across strata of race/ethnicity. For example, Black AYAs in the most vulnerable quintile had an increased risk (aHR = 1.50; 95% CI = 1.33, 1.68) of all-cause mortality compared to those in the least vulnerable SVI quintile. Additionally, there was an association between neighborhood vulnerability and all-cause mortality for each cancer stage, and the association increased as the quintile of SVI increased. For example, compared to those in the least vulnerable SVI quintile, AYAs in quintile two (aHR = 1.19; 95% CI = 1.11, 1.27), quintile three (aHR = 1.25; 95% CI = 1.17, 1.34), quintile four (aHR = 1.33; 95% CI =1.25, 1.42), and quintile five (aHR = 1.47; 95% CI = 1.38, 1.56) had elevated risks of all-cause mortality.
Conclusion
This study suggests that AYAs diagnosed with cancer experience the same disparities that have been previously reported in adult populations. Findings indicate that neighborhood vulnerability strongly predicts poor outcomes, regardless of race/ethnicity and stage, even after adjusting for key covariables. This study demonstrates that in addition to individual-level risk factors, geographic disparities may place individuals at a higher risk of poor outcomes or indicate other unmeasured factors.