2130 - Role of Postoperative Radiotherapy in Locally Advanced Esophageal Squamous Cell Carcinoma after Neoadjuvant Chemoimmunotherapy: A Retrospective Propensity Score-Matched Study

03:00pm - 04:00pm ET

Poster Hall - Exhibit Hall A

Screen: 23

POSTER

Presenter(s)

Li Li, - Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou,

L. Li¹, X. Jing², M. Sun³, Y. Wang³, Z. Sun⁴, Z. Shi³, H. Shi³, Y. Gao⁵, H. Zhu², C. Peng³, and J. Yu⁶; ¹Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou, China, ²Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, ³Affiliated Cancer Hospital of Shandong First Medical University, Shandong Cancer Hospital and Institute, Jinan, China, ⁴Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Science, Jinan, Shandong, China, ⁵Department of Pathology, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academic of Medical Science, Jinan, China, ⁶Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China

Purpose/Objective(s):

For patients who undergo neoadjuvant chemoradiotherapy but do not achieve pathological complete remission, adjuvant immunotherapy can improve disease-free survival (DFS). However, in the era of immunotherapy, the role of postoperative radiotherapy remains unclear in patients who undergo neoadjuvant immunochemotherapy (NCIT) followed by curative surgery. Therefore, we conducted a retrospective propensity score-matched (PSM) study to compare survival outcomes, failure patterns, and safety characteristics between patients receiving PORT and those receiving no PORT, aiming to provide new evidence to support individualized treatment strategies.

Materials/Methods: This retrospective study included patients with Locally Advanced Esophageal Squamous Cell Carcinoma (LA-ESCC) who underwent NCIT and achieved R0 resection between January 2020 and December 2023, and divided them into a postoperative adjuvant radiotherapy group (PORT) and a non-adjuvant radiotherapy group (non-PORT). Propensity score matching (PSM) was used to balance heterogeneity between the two groups. The primary endpoints were disease-free survival (DFS) and overall survival (OS). Secondary endpoints included failure patterns and treatment-related adverse reactions (AEs).

Results: A total of 318 patients were included in the study, with a median follow-up of 31.58 months. In the overall population, the 2-year DFS and OS rates were 68.1% and 81.1%, respectively. After PSM, median DFS was 20.46 months in the non-PORT group, whereas it was not reached (NR) in the PORT group (HR: 0.564, 95% CI: 0.345-0.922, p=0.020). Median OS was NR in both groups, with 2-year OS rates of 81.1% and 64.8%, respectively (p=0.040). Subgroup analysis indicated that patients with tumor regression grade 3 (TRG3) or positive lymph node status (ypN+) may benefit significantly from PORT. The distant metastasis rate in the PORT group was lower than that in the non-PORT group (p=0.046). The PORT group had higher rates of hematologic toxicity (75.68%) and radiation esophagitis (40.54%), though most reactions were Grade 1 or 2 AEs. The incidence of hematologic toxicity was similar between the two groups (p=0.139), but the incidence of Grade 4 neutropenia was lower in the PORT group (p=0.031).

Conclusion: For patients with LA-ESCC who undergo NCIT followed by R0 resection, PORT may improve DFS and OS, particularly in those with TRG3 or ypN+.