Epidemiology of lung cancer

This review article presents lung cancer epidemiology, describing main epidemiologic characteristics including epidemiological situation in cancer incidence, mortality and survival in Europe in comparison with situation in the Czech Republic. Influence of environmental and life style risk factors like smoking, passive smoking, risk factors of work environment, ionizing radiation, air pollution, nutrition and genetic and hormonal factors are discussed.     

Value of a multinational approach in determining the causation of cancer

MacMahon and Pugh define epidemiology as the use of knowledge on the frequency and distribution of disease to search for determinants. This paper demonstrates that a multinational approach in cancer epidemiology can be of great value in at least four circumstances: namely, the compilation and standardization of data, the assessment of risk, the pooling of study populations to obtain interpretable results, and the provision of resources for specific epidemiologic investigations. One or two examples are given for each category--the determination of international cancer incidence patterns, the evaluation of the risk posed by chemicals to man, assessment of the effects of low doses of ionizing radiation, determination of the long-term effects of exposure to asbestos substitutes, and studies on the influence of diet on esophageal cancer.     

Epidemiology of colorectal cancer

This review article presents colorectal cancer epidemiology, describing main epidemiologic characteristics and the influence of environmental and life style risk factors. The most important ideas for primary prevention are listed at the end of the article.     

The Epidemiology of Cancer in Animals

The principles of epidemiology are applicable to the study of the distribution and determinants of cancer in both human and animal populations. There are many examples of epidemiologic factors (host, environment, agent and time) related to cancer in animals. Certain host characteristics such as age, sex and breed are related to risk of developing cancer. Some environmental influences are illustrated by differences in the geographical distribution of certain types of animal cancer.Aggregations of cancer cases have been reported in herds, families and households. However, the usual distribution of cases in a population does not resemble epidemics typical of infectious diseases. Several factors (radiological, chemical, dietary, parasitic, mechanical, genetic and viral) have been identified as influences that affect the development of animal tumors.Animal species that have been domesticated live longer and consequently malignant disease develops in more of them. Cancer incidence rates now available from data compiled by an animal neoplasm registry in Alameda and Contra Costa counties, California, indicate that some of the frequent sites of cancer in man (skin, breast and the hemic and lymphatic systems) are among the most frequent sites in dogs and cats, man''s closest animal associates.     

Cancer incidence and spectrum among Uygurs in Hotan District in China

Cancer is the leading cause of death in China and a significant public health problem with increasing incidence and fatality rates. The Han nationality is the main ethnic group in China, and many reports on the epidemiology of cancers in Han nationality are published. However no studies report the cancer spectrum of Uygurs which are one of the minority nationalities in China. Hence, we present incidence and mortality numbers of different cancers for the Uygur patients for the period 2018–2020 in Hotan District where Uygur population accounts for 99 %. During the 3-year study period, 2509 new Uygur cancer cases were registered, comprising 774 men and 1735 women. Cervical cancer was the most common, followed by esophageal, breast, gastric and colorectal cancers. The most common cancers in women and men were cervical cancer and esophageal cancer, respectively. In conclusion, the cancer spectrum in Hotan is different from other regions of China and our research revealed the cancer incidence in Hotan, which could help us to take appropriate measures to reduce the incidence rate.     

Research on smoking and lung cancer: a landmark in the history of chronic disease epidemiology

This paper describes the history of the epidemiologic research on lung cancer prior to 1970 and its effect on chronic disease epidemiology. In the 1930s, epidemiology was largely concerned with acute infectious diseases. As the evidence grew that the incidence of lung cancer was increasing among men, however, epidemiologists undertook research into the etiology of the disease. In 1950, Doll and Hill, in England, and Wynder and Graham, in the United States, published substantial case-control studies that implicated the use of tobacco as a major risk factor for the disease. A controversy developed over the credibility of this finding and was increased in 1954 when a cohort study by Doll and Hill and another by Hammond and Horn each gave estimates that the risk of lung cancer was greatly increased among smokers relative to the risk among comparable non-smokers. An account is given of the disputes surrounding these and related studies. The controversy had a stimulating effect in fostering the developing discipline of chronic disease and epidemiology.     

Pilot study of extremely low frequency magnetic fields emitted by transformers in dwellings. Social aspects

A large number of epidemiologic studies examining the potential effect of residential exposure to extremely-low frequency (ELF) magnetic fields and childhood leukemia have been published. Two pooled analyses [Ahlbom A, Day N, Feychting M, Roman E, Skinner J, Dockerty J, Linet M, et al. (2000). A pooled analysis of magnetic fields and childhood leukaemia. Br J Cancer. 83(5):692–698; Greenland S, Sheppard AR, Kaune WT, Poole C, Kelsh AM (2000). A pooled analysis of magnetic fields, wire codes, and childhood leukemia. Epidemiology. 11(6):624–634], which included the major epidemiologic studies on ELF magnetic fields and childhood leukemia showed twofold increase in childhood leukemia risk in association with residential ELF exposure above 0.3–0.4 μT. Based on “limited” epidemiologic evidence linking ELF exposure to childhood leukemia and “inadequate evidence” for carcinogenicity of ELF in rodent bioassays, the International Agency for Research on Cancer (IARC) classified ELF magnetic fields as a possible human carcinogen (2B classification) [International Agency for Research on Cancer (IARC) (2002). Non-ionizing radiation, Part 1: Static and extremely low-frequency (ELF) electric and magnetic fields. IARC monographs on the evaluation of carcinogenic risks to humans. Vol. 80. IARC Press: Lyon], confirmed by WHO on the basis of studies published after 2000 [World Health Organization. Extremely low frequency fields. In: 238 Environmental health criteria, Geneva: WHO; 2007]. The analysis of more recent studies of ELF magnetic fields and childhood leukemia had small findings and propose methodological improvements concerning the uncertainties in epidemiological approaches and exposure assessment, bias in selection of controls [Kheifets L, Oksuzyan S (2008). Exposure assessment and other challenges in non-ionizing radiation studies of childhood leukaemia. Radiat Prot Dosimetry. 132(2):139–147]. By the end of 2010, 37 countries had been identified for possible participation in the International study TRANSEXPO. The pilot work has been completed in five countries (Finland, Hungary, Israel, Switzerland and Bulgaria). In 2008, Bulgaria through the National Centre of Public Health Protection joined with pilot study in TRANSEXPO Project. At this first stage of the project our investigation was directed to performing measurements in dwellings with built-in transformer stations, collecting data of population and cancer registry and choosing the epidemiology design feasible for continuing the project. Taking into account the available sources of information in Bulgaria (different registers of the population) needed for epidemiological approach, it was found that the most appropriate epidemiology design would be the nested case-control study. Control group could be collected in accordance with the international requirements for such epidemiological studies. This approach could be modified in the course of the further study in order to ensure achievement of the purposes of the main international requirements of the study.     

Prostate cancer pathology, screening, and epidemiology

Recent advances in the understanding of prostate cancer pathology, screening methods, and epidemiology were discussed at the 11th International Prostate Cancer Update. Regarding pathology, Dr. Gary Miller enumerated several factors that lead to the perception of prostate cancer as "unpredictable." These include the disease's multifocal nature, variable progression rates, and the uncertainty regarding the point at which carcinomas metastasize. Screening methods have been the subject of research by the Laval University Prostate Cancer Screening Program since 1988. Dr. Fernand Labrie presented the results of this 10-year study. Dr. Daisaku Hirano presented data from his studies of prostate cancer epidemiology in Japan as compared to the United States. The role of environmental factors, particularly diet, in prostate cancer pathogenesis and development is supported by the increase of the disease in Japan, concurrent with the "westernization" of diet there. Finally, useful information was presented on new computer- and Internet-based diagnostic and research tools.     

环境、基因组与肿瘤

肿瘤是当前危害人类健康最严重的疾病之一。从某种程度上说,它是一种遗传性疾病,然而在肿瘤发生、发展的多个阶段里,环境因素及其它非遗传性因素也起到了明显的作用。现在认为单纯遗传因素仅能解释大约5%的肿瘤的发病机制,而大部分肿瘤的发病机制归因于外界环境因素与遗传性、获得性肿瘤易感性之间的协同作用。值得注意的是,部分肿瘤易感性来自人类基因组的多样性。因此,环境、人类基因组及肿瘤三者之间有密不可分的关系。综合所有来自流行病学和实验室研究的信息,净化环境、给予高危人群特殊的保护,将会逐渐降低肿瘤的发病率。 Abstract：Cancer is one of the most serious diseases that thre aten human being today.To some degree,it is a genetic disease but environmental and other nongenetic factors clearly play a role in many stages of neoplastic pr ocess.Genetic factors by themselves are thought to explain only about 5% of all cancer.The remainder can be attributed to external,“environment” factors that act in conjunction with both genetic and acquired susceptibility.Of note,part of the susceptibility is owing to the variety of human genome.So,environment,human genome and cancer have much to do with each other.Combining all of the informat ion from epidemiology and from research works in laboratory with policy-making and clinical works,purifying the environment,giving special protection to the po pulation at high risk,the mobility of cancer may decrease gradually in the future.     

Environment, genome and cancer.

Cancer is one of the most serious diseases that threaten human being today. To some degree, it is a genetic disease but environmental and other nongenetic factors clearly play a role in many stages of neoplastic process. Genetic factors by themselves are thought to explain only about 5% of all cancer. The remainder can be attributed to external, 'environment' factors that act in conjunction with both genetic and acquired susceptibility. Of note, part of the susceptibility is owing to the variety of human genome. So, environment, human genome and cancer have much to do with each other. Combining all of the information from epidemiology and from research works in laboratory with policy-making and clinical works, purifying the environment, giving special protection to the high risk population, the mortality of cancer may decrease gradually in the future.     

Perspectives on the molecular epidemiology of aerodigestive tract cancers

Improving laboratory techniques and the greater availability of genetic data have led to a flurry of publications from molecular epidemiologic studies on aerodigestive tract cancers. Inconsistent results have been observed in studies of sequence variants, due to limitations such as small sample size, possible detection of false positives, moderate prior probabilities that each SNP confers a substantial increase in cancer risk, and publication bias. Meta- and pooled-analyses were shown to be effective in elucidating modest increases in aerodigestive tract cancer risk attributable to sequence variants. Phenotypic assays developed to quantify an individual's DNA repair capacity have been applied to epidemiological studies on aerodigestive tract cancers. Epigenetic events have also been studied in tumor progression and as susceptibility factors for aerodigestive tract cancers, in smaller scale studies. It is imperative that limitations of previous studies are addressed for future research in the molecular epidemiology of aerodigestive tract cancers. Some recommendations for future research are to: (i) incorporate multiple markers of different types (ex. genotype and phenotype data), (ii) enhance statistical power by conducting studies with larger sample size, and developing consortia to coordinate research efforts, (iii) improve marker selection via a hybrid strategy of incorporating data on evolutionary biology and physico-chemical properties of amino acids, with haplotype/tag SNP data, (iv) employ novel statistical methods such as hierarchical modeling with Bayesian adjustments, false positive reporting probability and modeling of complex pathways. Consortia have been initiated for head and neck cancer (International Head and Neck Cancer Epidemiology Consortium (INHANCE)) and lung cancer (International Lung Cancer Consortium (ILCCO)) with the aim to share comparable data, to focus on rare subgroups such as nonsmokers and to coordinate laboratory analyses. Such collaborative efforts and integration across disciplines will be essential in contributing to the elucidation of genetic susceptibility to aerodigestive tract cancers.     

Transition of cancer in populations in India

Background & objectivesAn assessment of transition of cancer in India during the past 30 years, according to changes in demographic and epidemiologic risk factors was undertaken.Materials & methodsCancer registry data (http://www.ncdirindia.org), (population coverage <10%), was compared with transition in life-expectancy and prevalence on smoking, alcohol and obesity. We fitted linear regression to the natural logarithm of the estimated incidence rates of various cancer registries in India.ResultsBurden of cancer in India increased from 0.6 million in 1991 to 1.4 million in 2015. Among males, common cancers are lung (12.0%), mouth (11.4%), prostate (7.0%), and tongue (7.0%) and among females, they are breast (21.0%), cervix-uteri (12.1%), ovary (6.9%), and lung (4.9%) in 2012. Increased life-expectancy and population growth as well as increased use of alcohol and increased prevalence of overweight/obesity reflected an increase in all cancers in both genders except a reduction in infection-related cancers such as cervix-uteri and tobacco-related cancers such as pharynx (excludes nasopharynx) and oesophagus.Interpretation & conclusionTransition in demographics and epidemiologic risk factors, reflected an increase in all cancers in both genders except a reduction in a few cancers. The increasing incidence of cancer and its associated factors demands a planned approach to reduce its burden. The burden assessment needs to be strengthened by increasing the population coverage of cancer registries. Continued effort for tobacco prevention and public health efforts for reducing obesity and alcohol consumption are needed to reduce the cancer burden.     

肿瘤突变特征与病理分型的关联研究

准确评估肿瘤的病理亚型对诊断、治疗和预后至关重要。以往病理亚型的诊断主要依赖HE染色法和免疫组织化学法,而随着测序技术的不断发展,对患者进行基因型和表型特点的个体分析成为可能,将肿瘤病理分型与基因分型结合用于疾病分型、诊治选择和疗效判断的精准医学研究逐渐兴起。不同病理亚型的肿瘤细胞来源、致癌因素和临床表型均不尽相同,其在基因组上会留下特异“印迹”,即突变特征。本研究通过整合癌症基因组数据库(The Cancer Genome Atlas, TCGA)中肾癌、肺癌和食管癌的外显子测序数据,分别对3种肿瘤通过肿瘤基因突变特征进行肿瘤病理分型聚类和预测。首先通过非监督聚类方法将3种肿瘤分别按照24种突变特征进行聚类分析,其次通过随机森林法从24种突变特征中进一步选择对于区分不同病理亚型有显著性的突变特征并进行聚类分析,构建突变特征对3种肿瘤病理亚型的分型模型。在肾癌中,该模型准确率达到了100% (95% confidence interval (CI): 0.93~1.00),肺癌和食管癌中分别达到了78% (95% CI: 0.66~0.86)和84% (95% CI: 0.60~0.97)。以上研究结果表明,突变特征作为新型分子标记物,对肿瘤的病理分型、诊断,尤其是早诊具有一定的参考意义。     

The use of common genetic polymorphisms to enhance the epidemiologic study of environmental carcinogens

Overwhelming evidence indicates that environmental exposures, broadly defined, are responsible for most cancer. There is reason to believe, however, that relatively common polymorphisms in a wide spectrum of genes may modify the effect of these exposures. We discuss the rationale for using common polymorphisms to enhance our understanding of how environmental exposures cause cancer and comment on epidemiologic strategies to assess these effects, including study design, genetic and statistical analysis, and sample size requirements. Special attention is given to sources of potential bias in population studies of gene--environment interactions, including exposure and genotype misclassification and population stratification (i.e., confounding by ethnicity). Nevertheless, by merging epidemiologic and molecular approaches in the twenty-first century, there will be enormous opportunities for unraveling the environmental determinants of cancer. In particular, studies of genetically susceptible subgroups may enable the detection of low levels of risk due to certain common exposures that have eluded traditional epidemiologic methods. Further, by identifying susceptibility genes and their pathways of action, it may be possible to identify previously unsuspected carcinogens. Finally, by gaining a more comprehensive understanding of environmental and genetic risk factors, there should emerge new clinical and public health strategies aimed at preventing and controlling cancer.     

Attributable causes of esophageal cancer incidence and mortality in china

Background

To estimate the contribution of tobacco smoking, alcohol drinking, low vegetable intake and low fruit intake to esophageal cancer mortality and incidence in China.

Methodology/Principal Findings

We calculated the proportion of esophageal cancer attributable to four known modifiable risk factors [population attributable fraction (PAF)]. Exposure data was taken from meta-analyses and large-scale national surveys of representative samples of the Chinese population. Data on relative risks were also from meta-analyses and large-scale prospective studies. Esophageal cancer mortality and incidence came from the 3^rd national death cause survey and population-based cancer registries in China. We estimated that 87,065 esophageal cancer deaths (men 67,686; women: 19,379) and 108,206 cases (men: 83,968, women: 24,238) were attributable to tobacco smoking, alcohol drinking, low vegetable intake and low fruit intake in China in 2005. About 17.9% of esophageal cancer deaths among men and 1.9% among women were attributable to tobacco smoking. About 15.2% of esophageal cancer deaths in men and 1.3% in women were caused by alcohol drinking. Low vegetable intake was responsible for 4.3% esophageal cancer deaths in men and 4.1% in women. The fraction of esophageal cancer deaths attributable to low fruit intake was 27.1% in men and 28.0% in women. Overall, 46% of esophageal cancers (51% in men and 33% in women) were attributable to these four modifiable risk factors.

Conclusions/Significance

Tobacco smoking, alcohol drinking, low vegetable intake and low fruit intake were responsible for 46% of esophageal cancer mortality and incidence in China in 2005. These findings provide useful data for developing guidelines for esophageal cancer prevention and control in China.     

Skepticism, statistical methods, and the cigarette: a historical analysis of a methodological debate

The discipline of modern "risk factor" epidemiology was in its formative stages in the early 1950s, when epidemiologic studies revealed a strong association between cigarette smoking and lung cancer mortality. Many medical scientists and physicians were reluctant to accept these studies as a demonstration of causation because the methods were "statistical" and involved data collected in uncontrolled conditions outside the laboratory. But a substantial number of senior biostatisticians and epidemiologists also voiced concerns, albeit more methodologically sophisticated, about the quality of the evidence at the time. Statistical methods were just beginning to work their way into medicine and public health, and many epidemiologists and statisticians were concerned about the potential misuse of these methods by untrained investigators. When studies of smoking and lung cancer gained increasing publicity and were being used to recommend public health policies, some prominent epidemiologists and statisticians highlighted this debate in their efforts to pursue methodological reform. Participants in the debate over smoking and lung cancer saw the need for explicit and rigorous standards for evaluating etiologic hypotheses, but they held conflicting views about what those standards should be. These diverging views reflect an underlying tension within the discipline of epidemiology between the search for "objective" methods of scientific inference and the practical needs of public health research that persists today.     

Escalating burden of breast cancer in southern Thailand: Analysis of 1990–2010 incidence and prediction of future trends

BackgroundThailand is undergoing an epidemiologic transition, with decreasing incidence of infectious diseases and increasing rates of chronic conditions, including cancer. Breast cancer has the highest incidence rates among females both in the southern region Thailand and throughout Thailand. However, there is a lack of research on the epidemiology of this and other cancers.MethodsHere we use cancer incidence data from the Songkhla Cancer Registry to characterize and analyze the incidence of breast cancer in Southern Thailand. We use joinpoint analysis, age-period-cohort models and nordpred analysis to investigate the incidence of breast cancer in Southern Thailand from 1990 to 2010 and project future trends from 2010 to 2029.ResultsWe found that age-adjusted breast cancer incidence rates in Southern Thailand increased by almost 300% from 1990 to 2010 going from 10.0 to 27.8 cases per 100,000 person-years. Both period and cohort effects played a role in shaping the increase in incidence. Three distinct incidence projection methods consistently suggested that incidence rates will continue to increase in the future with incidence for women age 50 and above increasing at a higher rate than for women below 50.ConclusionsTo date, this is the first study to examine Thai breast cancer incidence from a regional registry. This study provides a basis for future planning strategies in breast cancer prevention and to guide hypotheses for population-based epidemiologic research in Thailand.     

Epidemiology in protection and prevention against environmental mutagens/carcinogens Examples from occupational medicine

Subjects occupationally exposed to potential mutagens/carcinogens represent the most suitable groups for epidemiological studies aimed at assessing the risk for the individual or the offspring. Several cancer risks to humans have been detected by epidemiological studies performed in occupational settings. Cancer epidemiology studies have been able (a) to identify specific occupations or agents associated with the risk; (b) to verify the results of experimental studies; (c) to test the effectiveness of changes in production or preventive measures in decreasing risks. Reproductive epidemiology has suggested a risk of spontaneous abortions or of malformation in the offspring of workers exposed to some chemicals or occupations, but data are often conflicting due to methodological problems. With the aim of early assessment of risk in mind, the epidemiological use of indicators of exposure or of the early effect of exposure to genotoxic agents is increasingly applied to occupational groups. Cytological monitoring of subjects at risk of occupational cancer of lung or bladder is carried out mainly to diagnose precancerous lesions of target tissues. Cytogenetic methods (chromosome aberrations, SCE, micronuclei) in somatic cells provide a means for detecting early effects of occupational exposure to known or potential mutagens/carcinogens in selected groups of individuals, but their significance is widely debated. Monitoring of urinary mutagenicity, as applied in nurses handling cytostatic drugs, is an example of how an indicator of exposure to genotoxins can be used to evaluate the impact of preventive measures. Among the perspectives, biochemical epidemiology seems to be promising in detecting individuals genetically susceptible to cancer.