A Comparison of Real-World Treatment Patterns and Clinical Outcomes in Patients Receiving First-Line Therapy for Unresectable Advanced Gastric or Gastroesophageal Junction Cancer Versus Esophageal Adenocarcinomas

Introduction Management of locally advanced, unresectable, or metastatic (adv/met) esophageal adenocarcinoma (EAC) follows clinical guidance for gastric cancer (GC) and gastroesophageal junction cancer (GEJC). However, evidence for these guidelines is based largely on patients with adv/met GC/GEJC, and generally excludes patients with EAC. It is currently unclear whether patients with adv/met GC/GEJC and adv/met EAC have similar demographics and clinical outcomes in real-world practice. Methods Adult patients diagnosed with adv/met GC/GEJC and adv/met EAC between January 1, 2011 and November 30, 2018 were identified (Flatiron Health database); patients with confirmed human epidermal growth factor receptor 2 (HER2)-positive tumors were excluded, and index was date of adv/met diagnosis. Median overall survival (OS) from start of first-line therapy until death/censoring was estimated by the Kaplan–Meier method. Multivariable analysis (Cox proportional hazards) was conducted to identify factors associated with OS. Results In total, 3052 patients were identified (adv/met GC/GEJC, n = 2083; adv/met EAC, n = 969). Patients with EAC were more likely to be male, have a history of smoking, have a higher body weight and body mass index, and were less likely to be Hispanic/Latino or Medicaid enrollees than patients with GC/GEJC. A similar proportion of patients with adv/met GC/GEJC (75%; n = 2326) and adv/met EAC (77%; n = 1573) received first-line therapy. Fluoropyrimidine plus platinum combinations were the most frequent first-line regimen in both groups (36%). Median OS was similar for patients with adv/met GC/GEJC and adv/met EAC (9.7 vs. 9.1 months, respectively; hazard ratio [95% confidence interval] 0.96 [0.87–1.06]; p = 0.4320). Conclusion Despite minor differences in baseline demographics, clinical outcomes for patients with adv/met GC/GEJC and EAC are similar. This supports the inclusion of patients with adv/met EAC in clinical trials assessing adv/med GC/GEJC.