Abstract C081: Racial and ethnic differences in cause-specific survival among gastric cancer patients and effect modification by sex: A US population-based study

Abstract

Abstract Background: In the US, gastric cancer (GC) often presents at an advanced stage and is relatively more common in male than female populations. Racial/ethnic minoritized communities bear a heavy burden of overall cancer mortality. Limited research has investigated cause-specific survival and none have evaluated this in GC patients by sex and race/ethnicity. The current study examined racial/ethnic differences in GC-specific survival among GC patients stratified by sex. Methods: We extracted data from GC patients aged 18-64 years in the 2007-2016 Surveillance Epidemiology and End Results (SEER) program. The survival event was measured as GC-specific death or censored at the time of death from other causes or at the last known follow-up. Sex at birth was categorized as “female/male.” Race/ethnicity groups included Asian or Pacific Islander (API), American Indian or Alaska Native (AIAN), Black, Hispanic, and White. Median GC-specific survival time (in months) was estimated using Kaplan-Meier, with comparisons using log-rank tests. Due to the effect modification of the association between race/ethnicity and GC-specific survival by sex (p<0.001), we performed stratified Cox regression assessing racial/ethnic differences in GC-specific survival, adjusting for clinicodemographic characteristics. Results: Of 5,529 GC patients, the mean age was 54.6 years (SD=8.1); 73.7% were male; most (54.2%) were White, followed by 19.4% Hispanic, 14.0% Black, 11.3% API, and 1.2% AIAN. The median GC-specific survival time was 27.0 months for White, 23.0 months for Black, 22.0 months for API, 14.0 months for AIAN, and 12.0 months for Hispanic female patients (p<0.001). The median GC-specific survival time was 23.0 months for API, 20.0 months for White, 18.0 months for Hispanic, 15.0 months for Black, and 12.0 months for AIAN male patients (p=0.006). In the stratified analysis, API (adjusted hazard ratio [aHR]=0.72, 95% CI: 0.55-0.93), White (aHR=0.68, 95% CI: 0.56-0.83), or Black (aHR=0.66, 95% CI: 0.51-0.85) female patients had a lower risk of death than Hispanic female patients; no differential GC-specific survival was observed between AIAN and Hispanic female patients (aHR=1.22, 95% CI: 0.57-2.59). However, White male patients had a greater risk of death than their Hispanic counterparts (aHR=1.18, 95% CI: 1.04-1.34); no differential GC-specific survival between AIAN (aHR=1.34, 95% CI: 0.88-2.04), Black (aHR=1.18, 95% CI: 1.00-1.39), or API (aHR=1.05, 95% CI: 0.88-1.26) and Hispanic male patients was observed. Conclusions: In this population-based sample, racial/ethnic differences in GC-specific survival among GC patients were modified by sex. The relationship between sex and race/ethnicity in GC-specific survival is nuanced. White men and Hispanic women have the highest burden of GC, and men have lower survival than women. These findings suggest the potential need for tailored interventions to improve survival outcomes across racial/ethnic patient populations. Citation Format: Jincong Q. Freeman, Ted O. Akhiwu, Joseph O. Atarere, Adam W. Scott. Racial and ethnic differences in cause-specific survival among gastric cancer patients and effect modification by sex: A US population-based study [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C081.