3088 - Pathological Response and Survival Outcome after Neoadjuvant Chemoradiotherapy vs. Immunochemotherapy for Patients with Locally Advanced Esophageal Squamous Cell Carcinoma

S. Cheng¹, Y. Wu², W. Jianing³, Q. Zhao⁴, Z. G. Zhou⁵, Y. Liu⁶, B. Fan⁴, Y. Wang⁵, J. Wang², and L. Wang⁴; ¹Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, ²Department of Radiation Oncology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, China, ³the Fourth Hospital of Hebei Medical University, Hebei Clinical Research Center for Radiation Oncology, Shijiazhuang, Hebei, China, ⁴Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, ⁵Fourth Hospital of Hebei Medical University, Shijiazhuang, China, ⁶Department of Pathology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China

Purpose/Objective(s): Neoadjuvant chemoradiotherapy (nCRT) is recommended for resectable locally advanced esophageal squamous cell carcinoma (LA-ESCC). So far, studies of neoadjuvant chemotherapy and immunotherapy (nCIT) on ESCC are phase II studies and mainly focus on short-term pathological responses. We conducted a multicenter study to compare the pathological response and survival outcome of nCRT with nCIT for patients with resectable LA-ESCC. Materials/

Methods: A multicenter retrospective analysis of ESCC patients who underwent nCRT or nCIT followed by esophagectomy was performed. A 1:1 propensity score matching (PSM) with a caliper of 0.08 was conducted to balance potential bias. The pathological response of the primary tumor was evaluated by the College of American Pathologists (CAP) tumor regression grade (TRG) scoring system. The survival outcomes were overall survival (OS) and disease-free survival rates (DFS) at 12 months, 18 months, and 24 months. And the EC-specific mortality and other-cause mortality were estimated using Gray’s test.
Results: A total of 417 patients were included initially, and after PSM, 176 comparable pairs were selected for the final analysis. The rates of TRG 0 in primary tumor and pathologic complete response (pCR) in the nCRT group were significantly higher than in the nCIT group (54.5% vs. 27.3%, P<0.001; and 44.3% vs. 22.7%, P<0.001, respectively). As a result of survival analysis, the 12-, 18-, and 24-month DFS were 90.4%, 85.2%, 84.1%, and 83.0%, 68.2%, 67.0%, respectively (P= 0.107; P<0.001; P=0.001, respectively). The 12-, 18-, and 24-month OS rates in the nCRT group were 96.6%, 95.5%, 92.6%, and 90.3%, 84.7%, 81.8% in the nCIT group (P= 0.018; P<0.001; P=0.002, respectively). For patients with pCR, there was no significant difference in DFS and OS between nCRT and nCIT (DFS, P=0.494; OS, P=0.129). While for patients with non-pCR, nCRT obtained superior 18- and 24-month DFS and OS than nCIT (18-month DFS: 80.6% versus 63.2%, P=0.004; 24-month DFS: 78.6% versus 61.8%, P=0.006; 18-month OS: 93.9% versus 83.1%, P=0.013; 24-month OS: 89.8% versus 80.1%, P=0.046). An important high risk of anastomosis and tumor bed recurrence was observed in the nCIT compared with the nCRT (3.4% versus 0, P=0.040). The incidence of grade 3 and above adverse effects was substantially higher in the nCRT group than in the nCIT group (23.8% versus 2.3%, P<0.001).
Conclusion: In conclusion, compared with nCIT, nCRT for patients with LA-ESCC has an advantage in pathological response and could improve 2-year DFS and OS rates, while closer attention should be paid to grade 3 or more adverse reactions. More long-term and large-sample survival validation is still needed further validation.