Chronic infection and other risk factors of cancer in China and other countries

Abstract

The recent article by J. B. Wang [1.Wang J.B. Jiang Y. Liang H. et al.Attributable causes of cancer in China.Ann Oncol. 2012; 23: 2983-2989Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar] provided for highly interesting reading. The article concluded that the modifiable risk factors explain nearly 60% of cancer deaths in China, with a predominant role of chronic infection and tobacco smoking. Their findings could provide a basis for cancer prevention and control programs aimed at reducing the cancer risk in other developing countries. Interestingly, the past few years have seen the emergence of new data that suggest that chronic infection may have a significant role in and be an attributable cause of cancer in China and other countries [2.WHO Global health risks: mortality and burden of disease attributable to selected major risks. World Health Organization, Geneva2004Google Scholar]. In the recent data of World Health Organisation (WHO), the estimated attributable fraction of cancer for all infections combined was 16.1%. Most of the infection-attributable cases occurred in less developed countries and were due to preventable or treatable infections [3.Danaei G. Global burden of infection-related cancer revisited.The Lancet Oncology. 2012; 13: 564-565Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar]. The attributable causes of cancer include the known risk factors and unknown risk factors. The known risk factors of cancer are the selected risk factors of cancer evaluated by the International Agency for Research on Cancer (IARC) and other researches. The selected known risk factors of cancer based on the including criteria [1.Wang J.B. Jiang Y. Liang H. et al.Attributable causes of cancer in China.Ann Oncol. 2012; 23: 2983-2989Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar] are:(i)Agents that have sufficient evidence as human carcinogens according to the IARC monographs.(ii)Agents are causally associated with a reduced risk of cancer, according to IARC Cancer Prevention Handbook.(iii)Agents that have never been evaluated by the IARC, but with strong evidence for a causal association with cancer risk (e.g. reproductive factors and breast cancer risk). The unknown risk factors of cancer can be defined as the other risk factors apart from the known risk factors. Until now, the numbers of known risk factors of cancer are limited. There are lots of other risk factors of cancer which have not been evaluated by the IARC and other researches. Among the unknown risk factors of cancer, the agents of environmental pollution may be important risk factors of cancer. According to WHO latest data [4.WHO data repository, Total environment, Burden of disease. http://apps.who.int/ghodata/.2012-9-13Google Scholar], China is one of the most heavy losing country in total environment attributable deaths and 26% of deaths in China are attributable to the environment. So at present, the environmental pollution is the most important risk factor for people's health in China. It is known to all that in China, cancer is the main reason of death [5.The news of www.people.com.cn. Cancer has become the first reason of mortality in man-kind. Cancer specialists remarked that one third of cancer could be prevented. Re-published on Chinese National Health Daily. http://www.jkb.com.cn/document.jsp?docid=244787&cat=0IGoogle Scholar]. In 2004, WHO estimated the attributable fraction of cancer for the combined effect of nine lifestyle and environmental risk factors to be 35% [2.WHO Global health risks: mortality and burden of disease attributable to selected major risks. World Health Organization, Geneva2004Google Scholar]. All of these data have proved that environmental risk factors of cancer are the most attributable cause of cancer in China. In the other countries as well, the attributable causes of cancer also include the known and unknown risk factors. In order to prevent cancer effectively, all the cancer societies, government cancer prevention organizations and non-government organizations of cancer prevention, should not only pay attention to follow a policy for reducing the chronic infection and the other known risk factors of cancer, but also to reducing the unknown risk factors, especially the agents of environmental pollution. As a doctor to promote the health of Chinese and others around the world, I am obliged to write this article. I hope the Journal will publish my letter. With best regards! There is no conflict of interest for this paper.