Safety and efficacy of radiotherapy in combination with immunochemotherapy for advanced esophageal cancer: A retrospective analysis.

e16032 Background: Combining immune checkpoint inhibitors with chemotherapy has emerged as the standard treatment for advanced esophageal cancer. Radiotherapy could alleviate symptoms related to dysphagia. Additionally, it holds the potential to enhance the efficacy of immunotherapy, albeit with an associated risk of increased immunotoxicity. The combination of radiotherapy and immunochemotherapy for advanced esophageal cancer necessitates further investigation into its safety and efficacy. Methods: The medical records of consecutively treated patients with advanced esophageal cancer who underwent immunochemotherapy were retrospectively reviewed. The primary inclusion criteria were as follows: 1. Newly treated, imaging-confirmed stage IV esophageal carcinoma; 2. Radiotherapy administered within 6 cycles of immunochemotherapy; 3. Irradiation dose ≥ 30 Gy; 4. Target area must encompass esophageal neoplasms. The primary endpoints were overall survival (OS) and safety (RECIST 1.1). OS was defined as the time from initial treatment to the date of death. The secondary endpoint was progression-free survival (PFS), defined as the time from initial treatment to cancer progression or death. Median overall survival (mOS) time and median progression-free survival (mPFS) time were used to evaluate efficacy, while the incidence of adverse events (AEs) (CTCAE 5.0) was used to evaluate safety and feasibility. Kaplan-Meier survival analysis was conducted using SPSS25 software. Results: 122 patients were screened and 40 patients were finally included. The median age was 69. A total of 30 male patients were included. Three cases were stage IVa and 37 cases were stage IVb. Distant metastatic sites in these patients were lung (50%), liver (30%), bone (17.5%) and others. All cases were treated with immunochemotherapy as first-line treatment with median 4 cycles. Immunochemotherapy regimens are based on platinum and all treated with programmed death-1 inhibitors. Twenty-three cases were concurrent radiotherapy in combined with chemoimmunotherapy and 17 cases were sequential. For radiation therapy, the median dose was 50Gy in 25 fractions. The incidence of grade 3 and above AEs was shown in 20(50%) cases. Four (10%) patients showed treatment-related grade 5 toxicity (immune pneumonia, myocarditis, hepatitis and myocarditis complicated with hepatitis) which all occurred within 1-4 months after radiotherapy. With a median follow-up of 22.0 months, 26 (65%) cases experienced tumor progression (loco-regional progression only in 3, systemic progression only in 18, and both loco-regional and systemic progression in 5 patients), while 27 patients (67.5%) died. mOS and mPFS were 18.0 months and 6.2 months, respectively. Conclusions: Radiotherapy combined with immunochemotherapy for advanced esophageal cancer showed potential efficacy but relatively high toxicities.