RESUMO
PURPOSE: Breast cancer is the most common malignancy in women worldwide. In Nigeria, it accounts for 22.7% of all new cancer cases among women. Evidence-based medicine (EBM) entails using the results from healthcare research to enhance the clinical decision-making process and develop evidence-based treatment guidelines. Level 1 and 2 studies, such as randomized controlled trials, meta-analyses, and systematic reviews of randomized controlled trials, yield more robust types of evidence. This study reviewed the levels of evidence of breast cancer publications in Nigeria. METHODS: We conducted an electronic literature search of all studies published on breast cancer in Nigeria from January 1961 to August 2019. We reviewed all the articles found under the search term "Breast Cancer in Nigeria" on medical databases. RESULTS: Our search identified 2,242 publications. One thousand two hundred fifty duplicates were removed, and 520 were excluded. A total of 472 articles were considered eligible for this review. Most of these articles were case series or reports (30.7%), qualitative studies (15.7%), followed by cross-sectional studies (13.3%), laboratory studies (12.9%), case-control studies (6.1%), case reports (7%), and cohort (5.7%). CONCLUSION: Breast cancer research in Nigeria is yet to produce much evidence of the types considered to best support EBM. The scarcity of data hampers the implementation of EBM in Nigeria. Currently, most treatment guidelines are adapted from those developed in other countries, despite genetic differences among populations and different environmental influencing factors.