Potential Predictive Immune and Metabolic Biomarkers of Tumor Microenvironment Regarding Pathological and Clinical Response in Esophageal Cancer After Neoadjuvant Chemoradiotherapy: A Systematic Review.

"Disclosures Conflicts of interest to disclose that are relevant to this article."

"Funding No external funding was secured for this study. Helena H. Wang, Emelie N. Steffens, Gursah Kats-Ugurlu, Boudewijn van Etten, Johannes G.M. Burgerhof, Geke A.P. Hospers, and John T.M. Plukker have no financial relationships."

"A systematic review according to the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) guidelines was performed. The study protocol was registered and the search strategy was documented online at the International Prospective Register of Systematic Reviews Registry (PROSPERO; ID CRD42022325532). The research question was to explore potential predictive immune and metabolic biomarkers in the interaction of nCRT and TME for a more effective treatment strategy. The exact search strategy is provided in electronic supplementary material (ESM) Table . The EMBASE and PubMed online databases were searched from 2001 until September 2022 using the following inclusion criteria: (1) original article/conference abstracts; (2) studies on ESCC or EAC and/or GEA; (3) published in peer-reviewed journals from 2001 or later; (4) studies on the effect of the metabolic, immune and PET-based TME on PR and/or CR after neoadjuvant treatment; and (5) studies published in English. The exclusion criteria were (1) studies with missing or unclear description/criteria for groups and/or variables; (2) if full text was not available; (3) studies not assessing CR after nCRT on pre- and post-treatment PET/CT; and (4) studies not including pathologic reports of the esophageal biopsy and PR of the surgical resection material."