Treatment Outcomes and Patterns of Failure of Esophageal Cancer Patients Treated with Chemoradiation using Intensity-Modulation Radiation Therapy

Summary: Esophageal cancer accounts for over 500,000 deaths per year, worldwide. Esophagus cancer is often treated with chemoradiation based on findings from the CROSS study, which employed three-dimensional conformal radiation technique (3DCRT). Since then, intensity-modulated radiation therapy (IMRT) has been widely adopted in this setting. While expert contouring guidelines are available3, there is a paucity of clinical data, such as patterns-of-failure analysis or comparisons between different treatment volumes, that may guide the appropriate extent of elective coverage when using IMRT technique. This is an IRB-approved retrospective study primarily exploring anatomic patterns of failure after chemoradiation for esophageal cancer. We identified patients treated for esophageal cancer with curative intent chemoradiation, with or without surgical resection, at Loyola University Medical Center spanning from January 2015 to December 2023. We conducted chart review to collect demographic details, relevant comorbidities, tumor characteristics (such as stage, distance from incisors, and nodal involvement), and all treatments administered. Overall and recurrence-free survival were assessed. Recurrences were analyzed based on anatomic location (local vs. regional vs. distant), as well as position relative to radiation dose-maps (in order to characterize marginal recurrence). 58 eligible patients were identified. Demographic characteristics were notable for an average age of 69 years (range 47 to 84), 76% male patients, and 74.1% with smoking history. Histologies were 63.7% adenocarcinoma and 34.5% squamous cell carcinoma. 31 patients underwent surgical resection. 30 total recurrences were identified. 9 recurrences included local mucosal disease, 3 recurrences included regional nodes, and 24 recurrences included distant metastasis. Overall recurrence rates were lower in patients who underwent surgery (35%) than in patients who did not (76%) (p=0.008). Locoregional recurrence rates were 13% in patients who underwent surgery and 28% in patients who did not. Analysis on marginal recurrences and survival is underway. We found that distant recurrence predominates and that regional failures are relatively rare after the use of chemoradiation for esophageal cancer, supporting that the use of IMRT with standard elective volumes provides adequate regional coverage. Ongoing analysis will identify whether locoregional failures occurred out-of-field vs. marginal vs. in-field. Isaac Lasko (he/him/his), MD (Presenting Author) - Loyola University Hospital; Catherine Trelstad (she/her/hers), MS2 (Co-Author) - Stritch School of Medicine; Tamer Refaat (he/him/his), MD (Co-Author) - Loyola University Radiation Oncology