Real-world clinical characteristics and outcomes of patients with locally advanced, unresectable esophageal/gastroesophageal junction cancer (EC/GEJC) treated with definitive chemoradiotherapy (dCRT) in the United States community oncology setting

Adriana Valderrama^1*Karthik Ramakrishnan¹Lisa Herms²Helen Latimer²Junxin Shi²Gregory Patton²Sonal Bordia¹Sujatha Nallapareddy³

• ¹Merck & Co Inc, Rahway, United States
• ²Ontada LLC, Irving, United States
• ³Rocky Mountain Cancer Centers LLP, Colorado Springs, United States

Introduction: There are limited real-world data describing treatment patterns and clinical outcomes for patients with locally advanced, unresectable esophageal and gastroesophageal junction cancer (EC/GEJC) treated with definitive chemoradiotherapy (dCRT). Methods: This retrospective study included patients diagnosed with EC/GEJC who initiated dCRT between January 1, 2015, and June 30, 2021, within a large network of community oncology centers. Data from the electronic health record database were used. Demographic and clinical characteristics were evaluated in patients overall and stratified by disease recurrence status. Treatment characteristics, including index chemotherapy regimen and radiation dose, were assessed descriptively. Real-world time on treatment (rwTOT), real-world overall survival (rwOS), real-world event-free survival (rwEFS), and real-world recurrence-free survival (rwRFS) were assessed using Kaplan-Meier methods. Correlation between rwEFS and rwOS was estimated using Kendall-Tau's correlation coefficient. Results: A total of 17,427 patients were identified with a diagnosis of EC/GEJC. After meeting all eligibility requirements, 300 patients who initiated dCRT were included in the study population, with 37.3% of patients experiencing recurrence during follow-up; median follow-up time was 10.5 (interquartile range: 4.0, 21.0) months overall, with median follow-up of 14.1 months among patients with recurrence and 6.4 months among patients without recurrence. Carboplatin + paclitaxel (86.0%) was the most common chemotherapy with concurrent radiation treatment. Nearly half (46.3%) of the cohort received radiation dosing between 50-50.4 Gray. Median rwEFS was 8.9 (95% confidence interval [CI]: 7.7, 10.6) months, median rwRFS was 14.0 months, and median rwOS was 18.1 (95% CI: 13.3, 21.8) months. Landmark OS at 6 months for patients with recurrence was 7.1 (95% CI: 2.9, 13.2) months and 21.0 (95% CI: 17.6, 44.8) months for patients without a recurrence. Similarly, landmark OS at 12 months in the recurrence subgroup was 8.5 (95% CI: 6.8, 12.0) months and 41.5 (95% CI: 38.8, not reported [NR]) months in the non-recurrence subgroup. Furthermore, rwEFS and rwOS had a strong correlation (r = 0.8; 95% CI: 0.8, 0.9), indicating a delay in recurrence was associated with improved survival. Conclusion: The results of this analysis emphasize an unmet need for more effective therapies for EC/GEJC patients to prevent disease recurrence and improve outcomes.