035. THE EFFECT OF SURGICAL INTERVAL POST-NEOADJUVANT CHEMOIMMUNOTHERAPY ON LONG-TERM OUTCOMES IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background Although neoadjuvant immunotherapy combined with chemotherapy has shown promise in improving esophageal squamous cell carcinoma (ESCC) patient outcomes, the optimal timing for surgery after neoadjuvant chemoimmunotherapy is still unclear. Methods A prospective enrollment and retrospective analysis were conducted on 254 patients with locally advanced ESCC who underwent surgery following neoadjuvant chemoimmunotherapy between September 2020 and January 2024. Patients were divided into two groups based on the surgical interval after neoadjuvant chemoimmunotherapy: surgery within 8 weeks and surgery over 8 weeks. The impact of this interval on postoperative outcomes and prognosis was evaluated. Results A total of 254 patients were included in the study, 124 patients underwent surgery within 8 weeks after neoadjuvant chemoimmunotherapy, while 130 patients had surgery over 8 weeks. Among the patients who underwent surgery over 8 weeks, 31 patients (23.8%) achieved pathological complete response (pCR), and 14 of patients (11.3%) who underwent surgery within 8 weeks achieved pCR (P = 0.009). Long-term survival analysis demonstrated that patients underwent surgery over 8 weeks had significantly better overall survival (OS) (HR = 0.433, 95% CI = 0.233–0.806, P = 0.008) and disease-free survival (DFS) (HR = 0.451, 95% CI = 0.272–0.748, P = 0.002) compared to those who had surgery within 8 weeks. Conclusion Surgical interval of over than 8 weeks following neoadjuvant chemoimmunotherapy is associated with a higher pCR rate. Delayed surgery beyond 8 weeks appears to improve long-term survival outcomes in patients with locally advanced ESCC.