Social vulnerability and survival in GI cancers.

Abstract

787 Background: Social vulnerability is a federal metric used to assess a community’s resilience in facing external stressors from disease or disaster. The social vulnerability index (SVI) includes 15 social factors obtained at the census tract level within counties and ranks them along 4 themes – socioeconomic status, household composition and disability, minority status & language, and housing/transportation. Social vulnerability has never been explored at the census tract level in any malignancy and the Texas cancer registry provides granular detail at both the patient and census block group level not available in national datasets. We sought to characterize the relationship between social vulnerability and survival in gastrointestinal cancers, as well as its potential to identify themes for focused interventions to mitigate disparities. Methods: We retrospectively reviewed 196,651 patients with colorectal (CRC), gastric (GC), pancreatic (PDAC), and hepatocellular cancer (HCC) from the Texas Cancer Registry from 2004-2019. We analyzed patient demographics, social vulnerability (SVI), individual poverty index (PI), and clinicopathologic factors to understand their impact on survival at 2 years. Unadjusted and covariable-adjusted cox proportional hazards were used for survival analysis. Values were considered significant at p<0.05. Results: Of 196,651 patients, 119,667 (61%) were CRC, 31,636 (16%) PDAC, 18,249 (9%) GC, and 27,099 (14%) HCC. The majority of HCC were localized (51.4%) while most CRC was regional (38%) and PDAC (55%) and GC (40%) were metastatic at diagnosis (median 65 years). In our cohort, 60% of patients received surgery and 34% received chemotherapy while half of those with pancreatic/hepatic malignancies received no therapy. Percentiles for SVI themes were consistently near the national average except for GC which was in the 80th percentile for the minority/language theme. At 2 years, individual poverty at 5-9%, 10-19%, and >20% of the federal poverty line (HR 1.06, 95%CI 1.03 - 1.09; HR 1.09, 95%CI 1.06 - 1.12; HR 1.13, 95%CI 1.10 - 1.17) was associated with increased risk of death. Medicaid as primary insurance, (HR 1.41, 95%CI 1.36 - 1.47), SVI socioeconomic status (HR 1.18, 95%CI 1.13 - 1.24), and household composition themes (HR 1.06, 95%CI 1.02 - 1.10) also associated with increased likelihood of death at 2 years. Notably, the minority theme was associated with improved survival (HR 0.85, 95%CI 0.82 - 0.89). Conclusions: Across four GI cancers, social vulnerability and poverty independently predicted survival at 2 years. Among SVI themes, socioeconomic status was the strongest predictor of worse survival, and the minority theme was associated with improved survival, potentially reflecting the Hispanic paradox. These findings suggest that the SVI may be used as a tool for identifying where resources can be targeted at a local level to mediate the survival disparity for vulnerable populations with GI malignancies.