299. OPTIMAL NUMBER OF NEOADJUVANT IMMUNOTHERAPY AND CHEMOTHERAPY CYCLES IN ADVANCED ESOPHAGEAL CANCER TREATMENT

Abstract Background Neoadjuvant immunotherapy combined with chemotherapy (nICT) has shown potential benefits for patients with esophageal squamous cell cancer (ESCC) in clinical trials. However, the ideal number of nICT cycles for maximizing treatment outcomes in ESCC remains undetermined. This study aims to compare the short-term outcomes between two and three courses of nICT to establish the optimal approach for treating ESCC. Methods We conducted a retrospective analysis of clinical data from 118 patients with resectable locally advanced ESCC treated with nICT. Patients were divided into two groups: those who received 2 cycles of nICT (group A, n = 70) and those who received 3 cycles of nICT (group B, n = 48). The primary outcome was pathological complete response (pCR; ypT0 N0). Additionally, perioperative parameters and postoperative complications were examined. Results Overall, 28 patients (23.7%) achieved pCR. Group B, treated with 3 cycles of nICT, demonstrated a significantly higher pCR rate compared to group A (33.3% vs. 17.1%, P = 0.042). Postoperative complication rates were similar between the two groups (58.6% vs 54.2%, P = 0.635), and no significant difference was observed in anastomotic leakage rates (11.4% vs 6.3%, P = 0.522). Moreover, operation time (306.27 ± 87.05 vs. 306.13 ± 74.18 min, P = 0.996) and postoperative hospital stay (16.09 ± 10.55 vs. 15.04 ± 5.99 days, P = 0.537) did not significantly differ between the groups. Conclusion Three cycles of nICT led to better pathological responses compared to two cycles without increasing the incidence of postoperative complications. These findings can guide clinicians in counseling patients and inform the design of future prospective trials in ESCC treatment.