Environmental risk factors for gastric cancer: a protocol for umbrella review of meta-analyses

Abstract

Gastric cancer is the fifth most commonly diagnosed cancer globally, accounting for 5.7% of the new cancer cases in 2018[1]. Gastric cancer remains an important global concern because it is the third leading cause of cancer death[1] and its increasing incidence[2]. Therefore, it is crucial to develop prevention strategies for gastric cancer. Helicobacter pylori infection, a WHO class I carcinogen, is a significant risk factor of gastric cancer; however, only 0.5% of infected individuals would develop gastric cancer[3]. This data suggests that there are other additional risk factors for gastric cancer. A large body of research has been performed to investigate the association between various environmental factors and gastric cancer, including dietary factors, tobacco smoking, and alcohol drinking. However, the precision and strength of these existing studies need to be clarified. Umbrella review is one of the most useful tools for a clear understanding of a broad topic area. It provides a comprehensive overall picture of findings for specific questions based on high-level evidence of published systemic reviews and meta-analyses[4]. Thus, this study aimed to conduct an umbrella review of systemic reviews and meta-analyses that investigated gastric cancer risk factors.