Abstract
BACKGROUND: Esophageal cancer is a major global health threat, causing over 187,000 deaths in China in 2022. Esophageal squamous cell carcinoma (ESCC) patients face high recurrence risks postradical esophagectomy, with 28.5% - 54% experiencing relapse. Current guidelines lack strong evidence for salvage treatments. Although salvage concurrent chemoradiotherapy has shown potential in improving outcomes, the optimal irradiation fields remain unclear. Therefore, this study aimed to compare salvage involved-field irradiation (IFI) versus extended-field irradiation (EFI) with concurrent chemoradiotherapy in postoperative thoracic ESCC patients with lymph node metastases, assessing whether IFI reduces toxicity without compromising efficacy. METHODS: This retrospective study included 106 patients (2015-2024) treated with IFI (targeting involved nodes) or EFI (involved nodes + prophylactic areas) plus concurrent chemotherapy. Outcomes included local control rate (LCR), disease-free survival (DFS), overall survival (OS), disease control rate (DCR), objective response rate (ORR), adverse events (CTCAE v5.0), and elective nodal control (ENC, IFI group). RESULTS: With 57.2-month median follow-up, IFI and EFI showed comparable media OS (63.2 vs. 59.5 months, P = 0.519) and media DFS (28.4 vs. 17.8 months, P = 0.334). IFI achieved higher 3-/5-year LCR (81.1% vs. 61.8%; 60.8% vs. 49.4%, P = 0.026) and lower Grade 1-2 radiation esophagitis (29.3% vs. 46.9%), pneumonia (25.8% vs. 40.8%), and Grade 3-4 toxicity (32.8% vs. 57.1%, all P < 0.05). No significant differences in ORR/DCR were observed. IFI's ENC was 10.5% (6/57). CONCLUSION: Salvage IFI demonstrates non-inferior efficacy to EFI with significantly reduced severe toxicity (32.8% vs. 57.1%, P = 0.011) and potential survival benefits in single-node metastases, supporting its clinical prioritization. TRIAL REGISTRATION: This retrospective study was approved by the Ethics Committee of Jiangsu Cancer Hospital (Ethical Approval No. [KY-2024-020]).