Is a fusobacterium nucleatum infection in the colon a risk factor for colorectal cancer?: a systematic review and meta-analysis protocol

BACKGROUND: Despite a considerable amount of epidemiological research for identification of risk factors involved in the development of colorectal cancer, the current understanding of the etiology of this disease remains rather poor. Accumulating evidence suggests a potentially important role of infection with Fusobacterium nucleatum in the colon in colorectal carcinogenesis. The objective of this systematic review is to synthesize the epidemiological evidence on the association between infection with Fusobacterium nucleatum in the colon and colorectal cancer. METHODS: This systematic review will include observational studies (cohort, case-control, cross-sectional) in humans in which the role of Fusobacterium nucleatum in the etiology of colorectal cancer was investigated. MEDLINE, EMBASE, Web of Science, and Cochrane Database of Systematic Reviews will be searched using a comprehensive search strategy and manual screening of references. Two reviewers will independently identify eligible studies and extract the data from the included studies. The quality of studies will be assessed by using the Newcastle-Ottawa scale. Random-effects models will be used to estimate pooled measures of association (where feasible). Meta-regression and subgroup analyses will be conducted to explore the potential sources of heterogeneity. The Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement will be followed for reporting. DISCUSSION: Deepening knowledge regarding the etiology of colorectal cancer and the potential implications of Fusobacterium nucleatum in this disease is instrumental for prevention, diagnosis, and treatment of this often-fatal disease. This review will produce summarized current evidence on this topic. SYSTEMATIC REVIEW REGISTRATION: This systematic review protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 10 July 2018 (registration number CRD42018095866). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13643-019-1031-7) contains supplementary material, which is available to authorized users.