Comparison of efficacy and safety between pembrolizumab combined with chemotherapy and simple chemotherapy in neoadjuvant therapy for esophageal squamous cell carcinoma

Background: Immunotherapy can activate the recognition of tumor antigen, build immune memory, and more and more clinical trials have taken the scheme of immunochemotherapy or immunoradiotherapy as a treatment strategy for esophageal squamous cell carcinoma (ESCC). Our objective was to compare the efficacy and safety between pembrolizumab combined with the chemotherapy group and simple chemotherapy in neoadjuvant therapy of ESCC. Methods: Fifty-four ESCC patients with stage II-IVa were enrolled at the Fifth Affiliated Hospital of Sun Yat-sen University between January 2018 and December 2020, including 23 in the pembrolizumab combined with chemotherapy group (combined group), and 31 in the simple chemotherapy group. All patients received radical surgical treatment after two cycles of neoadjuvant therapy. Results: The pathological complete response (pCR) and objective response rate (ORR) in the combined group were significantly higher than that of the simple chemotherapy group (30.4% vs. 9.7%, P=0.048; 86.9% vs. 95.7%, P=0.017) as well as the score of tumor regression >= 2 (80.7% vs. 50.0%, P=0.013). And the complete rate of esophagectomy and R0 /R1 resection rate in the two groups were not statistically significant. Otherwise, the incidence of adverse events in the combined group was similar compared with the simple chemotherapy group. Conclusions: Pembrolizumab combined with chemotherapy showed promising activity with a manageable safety profile. And it could offer a potential new neoadjuvant treatment approach for patients with ESCC.