Northwestern China: a place to learn more on oesophageal cancer. Part one: behavioural and environmental risk factors

Abstract

Oesophageal squamous cell carcinoma (OSCC) remains a public health problem in many countries, especially in emerging and developing countries. Epidemiology of OSCC is characterized by marked differences in prevalence between countries/regions/ethnical groups. The highest incidence in the world is reached by populations living in specific areas of northwestern Xinjiang, China where age-adjusted mortality may reach 150 of 100 000. In fact, there are also marked differences among the various geographical areas and the various ethnic groups within the region, which suggests specific risk factors. Behavioural factors include those factors which are common to all 'high-risk populations', such as tobacco smoking and alcohol drinking. However, the very unusual sex ratio (1.2 : 1.0) and young age range of OSCC occurrence suggests the involvement of additional early risk factors shared by males and females, and which are different from those studied in other 'high-risk' areas of the world, including China, such as LinXian area. These include drinking very hot and salted tea, boiled with milk; a diet rich in meat, especially salted, dry and/or smoked meat, and dairy products; and a diet poor in fresh fruit and vegetables. The combination of hot drinks (such as milk, tea and soups) and high-degree spirit drinks, and hard food (bread, meat and cheese), together with poor oral hygiene and tooth loss, is likely to add mechanical injury of the oesophagus to other factors linked to climate characteristics of the area (drought) and dietary habits, which promote a sodium and nitrosamine-rich diet. Association of early and severe hypertension in the same populations at high risk of OSCC might likely raise more attention. Human papilloma virus (HPV) infection, and especially HPV 16/18 E6/E7, with gene mutations and association with p53 overexpression, may contribute to the extremely high incidence of OSCC observed in Xinjiang, and could be accessible to prevention. Infection may especially be a crucial additional factor in the Uygur population in which not only HPV infection but also infection with other oncogenic viruses, such as HHV8, are highly prevalent. Genetic polymorphism might interact with viruses and/or viral products to promote carcinogenesis. These observations in northwestern China suggest that usually neglected factors, such as sodium excess and viral infection, could be taken into more account when studying OSCC risk factors in other parts of the world, especially Europe.

Esophageal Cancer: Epidemiological, Clinical and Histopathological Aspects over a 24-Years Period at Kamenge University Hospital, Bujumbura, Burundi

“…Also, it could be used as evidence in motivating a decree about alcohol and tobacco consumption in our country like it is done in some western countries. It seems to be a big challenge because people in Burundi have traditionally subscribed to the belief that alcohol constitutes a social link and its abuse becomes common, although it is one of the documented risk factors [1] [2].…”

“…Its incidence varies according to the regions worldwide. The main risk factors are tobacco addiction, alcohol abuse and Barrett's esophagus that constitute a precancerous lesion associated with the gastro-esophageal reflux disease (GERD) [1] [2]. The esophageal cancer problem has also been investigated at the cellular and immunological levels and mass cytological surveys allow many cases of early cancer to be detected and treated [3].…”

High Temperature of Food and Beverage Intake Increases the Risk of Oesophageal Cancer in Xinjiang, China

“…Xinjiang Uyghur Autonomous Region, located in the northwest of China, is one of the areas constituting the so-called 'Asian Oesophageal Cancer Belt' (Zheng et al, 2010). According to a survey undertaken in Yili, Xinjiang, between 2005 and2008, the incidence of oesophageal cancer was 30.2 per 100,000, much higher than the national average during the same period (Ainiwaer et al, 2011).…”

Epidemiological features of esophageal cancer. Squamous cell carcinoma versus adenocarcinoma

“…Another characteristic of EC is its incidence diversity, with high indices in Asian countries 3,4 and a milder incidence in European and American continents. A great diversity is also observed in Brazil, with four cases in every 100 thousand inhabitants in the North Region and 15 cases for the same size population in South Brazil 2 .…”