Postoperative adjuvant therapy for resectable esophageal cancer: A protocol of a systematic review and meta-analysis

BACKGROUND: Esophageal cancer is one of the most common malignant tumors, characterized by early metastasis and high degree of malignancy. Its morbidity ranks 7th among all malignant tumors and its mortality ranks 6th. Postoperative adjuvant therapy after esophagectomy can significantly improve the overall survival rate of patients with locally resectable esophageal cancer. With the breakthrough and progress of immunotherapy, the possibility of cure of esophageal cancer is greatly improved. Some clinical trials have reported that programmed death 1 (PD1) and programmed death ligand 1 (PDL1) inhibitors alone, compared with traditional platinum-based chemotherapy, can benefit patients and effectively extend the overall survival period of patients. We will conduct a systematic review and meta-analysis on the comparison of the efficacy of immunotherapy (PD1 and PDL1 inhibitors) alone and traditional platinum-based chemotherapy, so as to provide a reliable basis for clinicians to formulate the best chemotherapy regimen for patients with esophageal cancer after esophagectomy. METHODS: We will search Pubmed, Medline, Embase, Web of Science, Cancerlit, Google Scholar, and the Cochrane Central Register of Controlled Trials for related studies published before December 1, 2019 without language restrictions. Two review authors will search and assess relevant studies independently. Randomized controlled trials (RCTs) or quasi-RCTs, and prospective cohort studies will be included. We will perform subgroup analysis in sex, age, ethnicity, and tumor stage of esophageal cancer patients. RESULTS: The results of this study will be published in a peer-reviewed journal. CONCLUSION: The results of this systematic review and meta-analysis will provide a basis for clinicians to formulate the best chemotherapy regimen for patients, as well as a research clue for clinical researchers in this field. The results of this study will expand the treatment options for esophageal patients, but due to the nature of the disease and intervention, large sample clinical trials are not abundant, so we will include some high-quality small sample trials, which may cause high heterogeneity. PROSPERO registration number: CRD42019125000.