Tropical Gastroenterology & Nutrition group, University of Zambia School of Medicine, Lusaka, Zambia.
Trans R Soc Trop Med Hyg. 2012 Feb;106(2):69-74. doi: 10.1016/j.trstmh.2011.11.002. Epub 2011 Dec 1.
Gastric cancer is a major contributor to mortality worldwide, yet its incidence varies widely around the world in a way which our current understanding of aetiology cannot fully explain. Incidence data from Africa are weak, reflecting poor diagnostic resources, but there are firm data on intestinal metaplasia and gastric atrophy which are important steps in the carcinogenesis pathway. The available registry data suggest that incidence is unlikely to be dramatically different from Europe or North America. Helicobacter pylori infection is an important permissive factor in the development of cancer, but H. pylori seroprevalence is high all over Africa and cannot clearly be correlated with cancer. However, there is evidence that specific bacterial virulence genes, particularly vacA and iceA allele1, do contribute to cancer risk. Intestinal metaplasia and gastric atrophy have been the focus of twelve studies and are common in Africa. Epstein-Barr virus, which causes 10% of cancer worldwide, is the focus of only one African study. Work in other continents demonstrates that other risk factors apply only to one or other of the two major histological types, intestinal and diffuse. Diet, smoking, alcohol and salt intake predispose to the intestinal type of cancer, but genetic factors predispose to the diffuse type. There is a pressing need for information on the histological types occurring in Africa, and their associated risk factors. Most urgently, information on dietary predisposition to cancer is required to inform public health policy with respect to the demographic transition (urbanisation and lifestyle changes) which is occurring all over the continent.
胃癌是全球主要的死亡原因之一，但在全球范围内，其发病率差异很大，我们目前对病因学的理解还无法完全解释这一现象。非洲的发病率数据很薄弱，反映出诊断资源不足，但有关肠化生和胃萎缩的数据是明确的，这是癌症发生途径中的重要步骤。现有的登记数据表明，发病率与欧洲或北美不太可能有显著差异。幽门螺杆菌感染是癌症发展的一个重要许可因素，但整个非洲的幽门螺杆菌血清阳性率都很高，与癌症无法明确相关。然而，有证据表明，特定的细菌毒力基因，特别是 vacA 和 iceA 等位基因 1，确实与癌症风险有关。肠化生和胃萎缩一直是 12 项研究的重点，在非洲很常见。导致全球 10%癌症的 Epstein-Barr 病毒仅成为非洲的一项研究的焦点。其他大洲的研究表明，其他风险因素仅适用于两种主要组织学类型中的一种或另一种，即肠型和弥漫型。饮食、吸烟、饮酒和盐摄入易患肠型癌症，但遗传因素易患弥漫型癌症。迫切需要了解非洲发生的组织学类型及其相关的风险因素。最紧迫的是，需要了解饮食对癌症的易感性，以便就非洲大陆正在发生的人口结构转变（城市化和生活方式改变）制定公共卫生政策。
