F1000推荐癌症研究里程碑新成果

　　生物通报道：“F1000（Faculty of 1000 Medicine）”又名“千名医学家”，是由美国哈佛大学和英国剑桥大学等全世界2500名国际顶级医学教授组成的国际权威机构。

来自国际癌症研究机构的研究人员公布了一项癌症肿瘤学研究领域的重要成果——他们通过分析2008年全球184个国家的27种癌症的数据，指出大约200万，或者说六分之一的世界新发癌症患者是由于感染引起的，并且这些感染是可以预防和治疗的。这对于癌症研究来说无疑意义重大，这一研究成果公布在Lancet Oncology杂志上。

这项研究由总部设在法国的国际癌症研究机构主导完成，文章通讯作者Martyn Plummer表示，细菌、病毒和寄生虫是最大的致癌因素，尽管这些因素是可以避免的。“利用现有医疗框架中的服务如疫苗、安全注射、抗菌措施等预防感染，会对未来减轻癌症给全球带来的巨大负担产生积极影响。”此外，专家称胃癌可以通过服用抗生素防止幽门螺旋菌感染内脏来避免。

对于这一研究成果，F1000成员，GSK的Mark Doherty（未参与研究）评价道，通常而言癌症是被认为是发达国家的一个主要健康问题，虽然最贫困国家中癌症的死亡数最高，要评估潜在需要预防的数量，并不容易。这项研究由传染疾病机构来评估，进行了系统的分析……

这项研究分析了27种癌症在184个国家的发病率，发现它们主要由四种感染引起，即人类乳头状瘤病毒(human papillomaviruses)、幽门螺旋杆菌(Helicobacter pylori)、乙型肝炎(hepatitis B)及丙型肝炎(hepatitis C)。据信这几种细菌和病毒导致了约190万子宫颈癌、肠癌和肝癌病例。大多此类疾病出现在发展中国家。这些病原体引发的感染现在基本上都有预防或治疗的方法，如有针对乙肝病毒和人乳头瘤病毒的疫苗，对幽门螺杆菌则可用抗生素治疗。

具体来说，全球范围内，女性宫颈癌和子宫癌的新发患者中有一半是由感染引起的，而男性肝癌和肠道肿瘤新发癌症患者中与感染有关的超过80%。他们补充道，大约30%由感染造成的新发癌症患者年龄低于50岁。乙肝病毒感染导致肝癌，并且有疫苗可以防止感染，而人乳头状瘤病毒和宫颈癌有关。同时，抗菌治疗能够清除肠道内的幽门螺杆菌。

由此研究人员指出，现有的公共卫生预防感染的方法，如接种疫苗、安全注射、或抗菌治疗的运用，对未来减轻全球癌症负担有实质的影响。他们指出“2011年联合国关于非传染性疾病的高层会议强调了非传染性疾病的预防和控制不断增长的全球议程”，并且指出尽管肿瘤并没有归类为传染性疾病，但是简单的非传染性疾病范例不足以对付它，因为大多数癌症发病率与预防和治疗感染有关。

这项研究强调了需要在控制癌症方面优先考虑在国际上和地区间设立一个基本标准，尤其是在低收入和中等收入的国家。

（生物通：万纹）

原文摘要：

Global burden of cancers attributable to infections in 2008: a review and synthetic analysis

Background
Infections with certain viruses, bacteria, and parasites have been identified as strong risk factors for specific cancers. An update of their respective contribution to the global burden of cancer is warranted.
Methods
We considered infectious agents classified as carcinogenic to humans by the International Agency for Research on Cancer. We calculated their population attributable fraction worldwide and in eight geographical regions, using statistics on estimated cancer incidence in 2008. When associations were very strong, calculations were based on the prevalence of infection in cancer cases rather than in the general population. Estimates of infection prevalence and relative risk were extracted from published data.
Findings
Of the 12·7 million new cancer cases that occurred in 2008, the population attributable fraction (PAF) for infectious agents was 16·1%, meaning that around 2 million new cancer cases were attributable to infections. This fraction was higher in less developed countries (22·9%) than in more developed countries (7·4%), and varied from 3·3% in Australia and New Zealand to 32·7% in sub-Saharan Africa. Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses were responsible for 1·9 million cases, mainly gastric, liver, and cervix uteri cancers. In women, cervix uteri cancer accounted for about half of the infection-related burden of cancer; in men, liver and gastric cancers accounted for more than 80%. Around 30% of infection-attributable cases occur in people younger than 50 years.
Interpretation
Around 2 million cancer cases each year are caused by infectious agents. Application of existing public health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments, could have a substantial effect on the future burden of cancer worldwide.