3089 - Efficacy and Safety of Radiotherapy Combined with Chemoimmunotherapy vs. Chemoimmunotherapy Alone as First-Line Treatment for Advanced Esophageal Squamous Cell Carcinoma with Oligorecurrence

X. Lv¹, Y. Wang², J. Ai², Q. Wang², and J. Wang³; ¹Fourth Hospital of Hebei Medical University, Shijiazhuang, China, ²the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China, ³Department of Radiation Oncology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, China

Purpose/Objective(s): Oligorecurrence (OLR) is usually defined as the oligometastatic disease diagnosed without 6 months after diagnosis of the primary tumor and the patient is not under active systemic therapy at the time of OMD diagnosis. This study aims to assess the safety and efficacy of radiotherapy combined with chemoimmunotherapy (RCIT) versus chemoimmunotherapy (CIT) alone as the first-line treatment for esophageal squamous cell carcinoma (ESCC) with OLR. Materials/

Methods: We retrospectively evaluated 108 patients diagnosed with oligorecurrent ESCC who underwent RCIT or CIT as first-line treatment between June 2018 and December 2021. The study included 58 patients in the RCIT cohort and 50 in the CIT cohort. Propensity score matching (PSM) was utilized to simulate random allocation.
Results: Following 1:1 PSM, 44 well-paired patients were identified. The median follow-up was 32.7 months (95% CI: 29.5-35.9). Post-PSM analysis showed a better trend in progression-free survival (PFS) with the addition of radiotherapy [12.7 (95% CI: 10.0-15.4) vs. 8.1 (95%CI: 5.3-10.8) months, P=0.058]. Although overall survival (OS) revealed no significant differences between the RCIT and CIT groups (P=0.169), the RCIT group demonstrated prolonged OS [26.2 (95% CI: 14.5-37.9) vs. 14.1 (95% CI: 9.3-18.9) months]. Nonetheless, subgroup analysis showed that patients with 1-2 metastatic lesions (HR: 0.407, P=0.023), single recurrent organ (HR: 0.297, P=0.002), and no distant parenchymal organ recurrence (HR: 0.524, P=0.046) significantly benefited in terms of prolonged OS in the RCIT group. Similar trends were observed for PFS in patients with specific characteristics, including male gender (HR: 0.432, P=0.005), age under 65 (HR: 0.448, P=0.021), ECOG performance status of 0-1 (HR: 0.599, P=0.034), 1-2 recurrent lesions (HR: 0.493, P=0.027), single recurrent organ (HR: 0.423, P=0.005), =4 chemotherapy cycles (HR: 0.528, P=0.045), and no distant parenchymal organ recurrence (HR: 0.579, P=0.048). The incidence of grade 3 or higher treatment-related adverse events (TRAEs) did not significantly differ between the RCIT and CIT groups (34.1% vs. 25.0%, P=0.350).
Conclusion: RCIT as first-line treatment provides survival benefits for oligorecurrent ESCC patients with 1-2 recurrent lesions, single recurrent organ, and no distant parenchymal organ recurrence. RCIT did not increase the high-grade toxicity rate compared with CIT.