Radiotherapy improved the efficacy of immunotherapy for advanced esophageal cancer.

e16063 Background: The development of immunotherapy has changed treatment methods for advanced esophageal cancer (EC).However, the efficacy of ICIs in advanced EC is not ideal, and the clinical research on the combination of ICIs and Radiotherapy(RT) in advanced EC remains insufficient. This study aimed to evaluate the effectiveness and safety of radiation in first-line immunotherapy for advanced EC. Methods: We conducted 201 advanced EC patients who received first-line ICIs in West China Hospital. The enrolled patients were divided into 2 groups based on whether they received radiation therapy. Results: The analysis included data from 201 patients. The radiotherapy (RT) group had 103 patients (51.2%), whereas the non-radiotherapy (NRT) group included 98 individuals (48.8%). The RT sites include esophagus lesions (83, 80.6%), metastatic lymph nodes (11, 10.7%), liver metastases (4, 3.9%), bone metastases (2, 1.9%), brain metastases (2, 1.9%), lung metastases(1, 0.97%). The median radiation dose was 50.4 Gy (range, 12-68). The RT group had a median OS of 22.8 months (95% CI, 17.8-NA), which was longer than the NRT group's 14.6 months (95% CI, 12.8-26.5) (p = 0.038). And the median PFS was 12.9 months (95% CI, 11.2-14.0) in the RT group versus 7.3 months (95% CI, 6.3-9.7) in the NRT group (p = 0.006). Patients in the RT group had a higher disease control rate (DCR) (99.0% vs. 76.5%, P < 0.001). However, a higher proportion of patients in the RT group developed grade 3-4 myelosuppression (37.86% V.S. 20.20%, P = 0.006), and there was no significant difference in the other AEs. Conclusions: In the first-line immunotherapy for advanced esophageal cancer, radiotherapy has been attributed to improved survival with tolerable toxicity.