Conversion surgery following immuno-chemotherapy in initially-unresectable esophageal squamous cell carcinoma: A real-world multicenter study.

Abstract

e16045 Background: Currently, the real-world evidence is not available to support the practice of induction immunochemotherapy (iIC) plus conversion surgery for initially-unresectable esophageal squamous cell carcinoma (ESCC). This study aimed to evaluate the feasibility, safety and effectiveness of conversion surgery following iIC for advanced ESCC in a real-world scenario. Methods: In this multi-center, single-arm, real-world study (NCT04822103), patients who had unresectable cT4b ESCC tumors with evident involvement of the adjacent organs (aorta, trachea, or bronchus) or had multi-station, bulky lymphadenopathy were enrolled across eight medical centers in China. All patients received programmed death receptor-1 (PD-1) inhibitor plus chemotherapy every three weeks. Radiologcal assessment was performed for patients who completed at least two cycles of immunochemotherapy. In general, patients with significant relief of cancer-related clinical symptoms and radiological complete response/partial response disease were deemed surgical candidates. The primary endpoints were the objective response rate (ORR) per RECIST version 1.1 and safety profile per CTCAE version 5.0. Results: Between Nov 2019 and June 2021, 155 patients were enrolled in the final analysis. The numbers of patients with pre-treatment clinical stage III, and IVA were 21 (13.5%) and 134 (86.5%), respectively. Upon the completion of preoperative treatment, 6 (3.9%) patients achieved radiological complete response (CR), 92 (59.4%) achieved partial response (PR), and 45 (29.0%) achieved stable disease (SD), yielding an ORR and DCR of 63.3% and 92.3%, respectively. Esophagectomy was then offered to 116 patients who were considered suitable for surgery, yeilding a conversion rate of 74.8%. 109 out of 116 patients achieved R0 resection. Pathological complete response (pCR) of the primary tumor was observed in 26 (22.4%) patients, with 25 (21.6%) of them achieving pCR in both primary tumor and metastatic lymph nodes. Most patients (111/116, 95.7%) had a downstaging in tumor invasion depth. However, downstaging of nodal metastasis was observed in 48 (48/116, 41%) patients. Thirteen patients (13/116, 11.2%) had progressive nodal response. Among the treated patients, 69.0% (107/155) patients experienced at least one treatment-related adverse event (TRAEs), while 29% (49/155) had grade three or higher (G ≥ 3) TRAEs, including leukopenia (20/155, 12.9%), neutropenia (18/155, 11.6%), rash (12/155, 7.7%), diarrhea (6/155, 3.9%), and infection (6/155, 3.9%). Conclusions: We demonstrated that conversion surgery following immunochemotherapy is feasible, safe and effective for initially-unresectable ESCC patients. Further larger-scale studies are needed to establish the standard-of-care use of iIC in the preoperative settings for initially-unresectable ESCC patients.