Global research trends in fecal microbiota transplantation combined with immune checkpoint inhibitors for cancer immunotherapy: a bibliometric analysis.

Background: Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment by restoring antitumor immune responses. However, heterogeneous efficacy, primary or acquired resistance, and immune-related adverse events (irAEs) remain major clinical challenges. There is evidence that gut microbiota critically regulate ICI efficacy, and fecal microbiota transplantation (FMT) has emerged as a promising intervention to improve therapeutic outcomes. Here, we performed a bibliometric analysis to map global research trends, hotspots, and frontiers in FMT combined with ICIs for cancer immunotherapy. Methods: A range of scientometric tools, including CiteSpace, VOSviewer, Bibliometrix R package, and Tableau, were employed to retrieve and analyze the literature on FMT combined with ICIs for cancer immunotherapy from the Web of Science Core Collection for the period from 2015 to 2026. The analyses covered national and institutional collaboration networks, the identification of highly productive authors, journal impact and publication trends, co-cited reference analysis, as well as keyword co-occurrence, clustering, and burst detection. Results: A total of 345 relevant publications were identified, with annual output rising rapidly since 2019 and reaching a peak in 2025. China ranked first in publication volume, while the United States showed the highest centrality in international collaboration. The leading research institutions were the University of Texas MD Anderson Cancer Center, Shanghai Jiao Tong University, and Université Paris-Saclay. Routy, Bertrand and Wang, Yinghong were prominent high-impact authors. Co-citation and keyword analyses revealed a shift in research focus from gut microbiota-mediated regulation of ICI efficacy to clinical translation of FMT for reversing resistance, and further to mechanistic insights into microbial metabolites and the tumor microenvironment (TME). Further keyword analysis demonstrated that FMT research has expanded to digestive system malignancies, including colorectal, gastric, and hepatocellular carcinomas (HCCs). Current research hotspots include "dysbiosis", "dietary fiber", "chain fatty acids", "tumor microenvironment", "consensus statement", and "international scientific association". Conclusions: This bibliometric analysis reveals that the research field of FMT combined with ICIs has evolved from descriptive correlations to mechanism-driven research, with an expanding focus on digestive system tumors. Future research should prioritize large-scale randomized controlled trials (RCTs) and standardized clinical protocols, underpinned by in-depth mechanistic studies, to advance microbiome-based precision cancer immunotherapy.