3539 - Radiotherapy as an Organ-Preserving Alternative to Surgery in Patients with Locally Advanced Esophageal Squamous Cell Carcinoma Achieving Major Pathologic Response after Induction Immunochemotherapy

02:30pm - 03:45pm PT

Hall F

Screen: 10

POSTER

Presenter(s)

Xin-Yun Song, MD - Shanghai Chest Hospital, Shanghai, Shanghai

X. Y. Song¹, L. Lin¹, H. H. Hu¹, Y. Yang², Z. Li², W. Yu¹, J. Liu¹, and X. L. Fu¹; ¹Department of Radiation Oncology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, ²Department of Thoracic Surgery, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China

Purpose/Objective(s): Organ-saving strategies, including radiotherapy and active surveillance, have shown comparable survival outcomes to standard esophagectomy in patients who achieve a clinically complete response (cCR) after neoadjuvant chemotherapy or chemoradiotherapy. With the advent of immunotherapy, neoadjuvant immunochemotherapy has shown promising efficacy in locally advanced esophageal squamous cell carcinoma(ESCC). However, it remains unclear whether radiotherapy can serve as a viable organ-preserving alternative following induction immunochemotherapy (IICT), and which patient subgroups would derive the most benefit from this approach.

Materials/Methods: This retrospective study included patients with locally advanced ESCC who underwent either radiotherapy or surgery following IICT from January 2021 to June 2023. Responses to immunochemotherapy were classified as major pathologic response (MPR) or non-MPR based on pathologic examination for surgical patients and a previously developed MPR predictive model for radiotherapy patients. Survival outcomes were calculated from the start of IICT using the Kaplan?Meier method, and univariable and multivariable Cox regression analyses were performed to identify prognostic factors. One-to-one propensity score matching (PSM) was applied to adjust for confounding factors.

Results: A total of 388 patients were included, with 299 receiving surgery and 89 receiving radiotherapy following IICT. Surgery after IICT was associated with better progression-free survival (PFS) compared to radiotherapy (before PSM: p=0.002; after PSM: p=0.017), but there was no significant difference in overall survival (OS) between the two groups (before PSM: p=0.144; after PSM: p=0.241). When patients were stratified by response to IICT, radiotherapy demonstrated non-inferior survival outcomes to surgery in both PFS and OS for MPR patients after PSM (PFS: p=0.136; OS: p=0.255). For non-MPR patients, surgery was associated with better PFS, although OS benefits were not significant after PSM. Local or regional recurrence was the predominant failure pattern in the radiotherapy group, while over 60% of patients in the surgery group experienced progression due to distant metastasis. Major postoperative complications occurred in 9.36% (28/299) of surgery patients, and 11.2% (10/89) of radiotherapy patients experienced grade 3 or higher non-hematological treatment-related adverse events during or after radiotherapy.

Conclusion: Radiotherapy following IICT may offer a safe and effective organ-preserving approach for patients with locally advanced ESCC, particularly those who achieve a major pathological response after immunochemotherapy.