Impact of Socioeconomic Factors on Survival in Locoregional Gastroesophageal Junction Cancer: A SEER‐Based Analysis

BACKGROUND: Gastroesophageal junction cancer is a rising global health concern with variable outcomes. The availability to high-volume cancer centers may influence survival, yet disparities related to geography and socioeconomic status remain poorly defined. METHODS: A retrospective cohort study was conducted using the SEER 21 Research Plus database (2000-2022). A total of 40,273 patients with locoregional gastroesophageal junction cancer were included. Patient-level variables included age, sex, race, histology, stage, and survival. Socioeconomic and geographic variables included county-level median household income and rural-urban residence. State-level volume was defined according to the number of high-volume esophageal cancer centers within each patient's state of residence: high-volume (≥ 2 centers), moderate-volume (1 center), and low-volume (no centers). The primary outcome was overall survival. Cox proportional hazards models were used to evaluate associations between patient-, socioeconomic-, geographic-, and state-level factors and survival. RESULTS: Residence in states with lower-volume centers was associated with worse outcomes than residence in states with high-volume centers. Each step toward lower-volume categories was associated with an increased hazard of death (HR 0.923, 95% CI 0.899-0.949, p < 0.001). While stage at diagnosis varied significantly across hospital volume categories (p < 0.001), no clear pattern of more advanced stage in lower-volume states was observed. Patients with adenocarcinoma had a 25% lower hazard of death compared to those with squamous cell carcinoma (HR 0.752, 95% CI 0.726-0.780, p < 0.001). Female gender was associated with a statistically significant increase in hazard of death compared to males (HR 1.042, 95% CI 1.013-1.072, p = 0.004). Additionally, higher median household income was associated with improved survival (HR 1.006, p < 0.001 per category increase), and urban residence (HR 1.036, p < 0.001) was independently associated with improved survival. CONCLUSIONS: Survival in locoregional gastroesophageal junction cancer is influenced by both tumor biology and healthcare access. Residence in states with high-volume centers, adenocarcinoma histology, higher income, and urban residence were independently associated with improved survival, highlighting disparities tied to regional resource availability within the United States.