Population attributable fraction of infection-related cancers in Korea

Association between obesity and cancer risk in adults with HIV in Korea

INTRODUCTION

This study aimed to investigate the association between obesity and cancer risk as well as site-specific cancer risks in adults with HIV using a nationwide health screening database in Korea.

METHODS

Of the 16,671 adults with a new diagnosis of HIV from 2004 to 2020, 456 incident cancer cases and 1814 individually matched controls by sex, year of birth, year of HIV diagnosis, and follow-up duration (1 : 4 ratio) were included in this nested case-control study. The association between obesity (BMI ≥25 kg/m 2 ) and cancer risks was estimated and presented as odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Of the 456 cancer incident cases, there were 146 AIDS-defining cancer cases and 310 non-AIDS-defining cancer cases. Compared with nonobese adults with HIV, obese adults with HIV were at higher risk of non-AIDS-defining cancer (OR = 1.478, 95% CI = 1.118-1.955). Otherwise, the overall risk of AIDS-defining cancer (OR = 0.816, 95% CI = 0.520-1.279) and each type of AIDS-defining cancer (Kaposi sarcoma and non-Hodgkin's lymphoma) were not high in obese adults with HIV. Of the specific types of non-AIDS-defining cancers, obesity was associated with an increased risk of colorectal cancer (OR = 3.090, 95% CI = 1.110-8.604) and liver, bile duct, and pancreatic cancers (OR = 2.532, 95% CI = 1.141-5.617).

CONCLUSION

Obesity, which is one of the important health concerns in HIV management, was associated with an increased risk of non-AIDS-defining cancer but not AIDS-defining cancer.

Proportion of cancer cases and deaths attributable to potentially modifiable risk factors in Peru

BACKGROUND

Limited evidence exists on the population attributable fraction (PAF) of cancer cases and deaths in Latin America. In Peru several studies have been published regarding the PAF of various risk factors and their associated diseases. The objective of this study was to estimate the fraction of cancer cases and deaths attributable to potentially modifiable risk factors in Peru in 2018, before the COVID-19 pandemic in the population of 15 years old and older.

METHODS

An ecological study was conducted using the prevalence of exposure of the Peruvian population to modifiable risk factors for cancer, the relative risk associated with each factor, and the number of cancer cases and deaths in 2018 as inputs. We used the Parkin formula with a Montecarlo statistical simulation model to calculate the PAF and confidence intervals. The number of new cancer cases and deaths attributed to each risk factor was determined by multiplying the number of cases and deaths in each gender by the PAF of each risk factor.

FINDINGS

In Peru, 38.5% of new cases (34.5% in men and 42% in women) and 43.4% of cancer-related deaths (43.4% in men and 43.4% in women) were attributable to modifiable risk factors. The number of cancers attributable was 25,308 (10,439 in men and 14,869 in women) and the number of deaths attributable to cancer was 14,839 (6,953 in men and 7,886 in women). The predominant modifiable risk factors contributing to the highest number of cases and deaths were HPV infection (4,563 cases, 2,409 deaths), current tobacco use (3,348 cases, 2,180 deaths), and helicobacter pylori infection (2,677 cases, 1,873 deaths). Among the risk factors, oncogenic infections constituted the group with the highest PAF (16.6% for cases, 19.2% for deaths) followed by other unhealthy lifestyle factors (14.2% for cases, 16.7% for deaths), tobacco (7.2% for cases, 7.2% for deaths) and ultraviolet radiation (0.5% for cases, 0.3% for deaths).

CONCLUSIONS

Prior to the COVID-19 pandemic, 38.5% of cancer cases and 43.4% of cancer-related deaths in Peru were linked to modifiable risk factors in the population of 15 years old and older. Most preventable cancer cases and deaths were related to oncogenic infections, primarily caused by HPV and helicobacter pylori, followed by tobacco and obesity.

Population attributable fractions of modifiable cancer risk factors in Korea: A systematic review

OBJECTIVES

The population attributable fraction (PAF), an epidemiologic measure of exposures and health outcomes, can provide information on the public health impacts of exposures in populations. This study aimed to systematically summarize the PAF estimates of modifiable cancer risk factors in Korea.

METHODS

This review included studies that determined PAFs of modifiable risk factors for cancer in Korea. We performed systematic searches in EMBASE, MEDLINE, Cochrane library, and Korean databases for studies published up to July 2021. Two reviewers independently screened studies for eligibility, extracted data, and performed quality assessments of the included studies. Due to high variability among the data acquisition methods and PAF estimates, we presented the results qualitatively and did not perform quantitative data synthesis.

RESULTS

We reviewed 16 studies that reported the PAFs of risk factors for cancer, including smoking, alcohol consumption, obesity, and various cancer sites. We found considerable variability in the PAF estimates across exposure and cancer pairs. However, PAF estimates for smoking and respiratory cancer were consistently high in men. PAF estimates were higher in men than in women for smoking and alcohol consumption but higher in women for obesity. We found limited evidence for other exposures and cancers.

CONCLUSION

Our findings may be used to prioritize and plan strategies to reduce cancer burden. We encourage further and updated assessments of cancer risk factors, including those not addressed in the studies included in this review, and their potential contributions to cancer burden to better inform strategies for cancer control.

Cancers attributable to infectious agents in Italy

OBJECTIVES

To provide an evidence-based, comprehensive assessment of the current burden of infection-related cancers in Italy.

METHODS

We calculated the proportion of cancers attributable to infectious agents (Helicobacter pylori [Hp]; hepatitis B virus [HBV] and hepatitis C virus [HCV]; human papillomavirus [HPV]; human herpesvirus-8 [HHV8]; Epstein-Barr virus [EBV]; and human immunodeficiency virus [HIV]) to estimate the burden of infection-related cancer incidence (2020) and mortality (2017). Data on the prevalence of infections were derived from cross-sectional surveys of the Italian population, and relative risks from meta-analyses and large-scale studies. Attributable fractions were calculated based on the counterfactual scenario of a lack of infection.

RESULTS

We estimated that 7.6% of total cancer deaths in 2017 were attributable to infections, with a higher proportion in men (8.1%) than in women (6.9%). The corresponding figures for incident cases were 6.5%, 6.9% and 6.1%. Hp was the first cause of infection-related cancer deaths (3.3% of the total), followed by HCV (1.8%), HIV (1.1%), HBV (0.9%), HPV, EBV and HHV8 (each ≤0.7%). Regarding incidence, 2.4% of the new cancer cases were due to Hp, 1.3% due to HCV, 1.2% due to HIV, 1.0% due to HPV, 0.6% due to HBV and <0.5% due to EBV and HHV8.

CONCLUSIONS

Our estimate of 7.6% of cancer deaths and 6.9% of incident cases that were attributable to infections in Italy is higher than those estimated in other developed countries. Hp is the major cause of infection-related cancer in Italy. Prevention, screening and treatment policies are needed to control these cancers, which are largely avoidable.

Burden of cancer attributable to modifiable factors in Japan in 2015

The This study estimated the cancer burden attributable to modifiable factors in Japan in 2015 using the best available epidemiological evidence and a standard methodology. We selected the following factors for inclusion in the estimates, namely tobacco smoking (active smoking and secondhand smoking), alcohol drinking, excess bodyweight, physical inactivity, infectious agents (Helicobacter pylori, hepatitis C virus, hepatitis B virus, human papilloma virus, Epstein-Barr virus, and human T-cell leukemia virus type 1), dietary intake (highly salted food, fruit, vegetables, dietary fiber, red meat, processed meat), exogenous hormone use, never breastfeeding and air pollution, given that these were considered modifiable, in theory at least. We first estimated the population attributable fraction (PAF) of each cancer attributable to these factors using representative relative risks of Japanese and the prevalence of exposures in Japanese around 2005, in consideration of the 10-year interval between exposure and cancer outcomes. Using nationwide cancer incidence and mortality statistics, we then estimated the attributable cancer incidence and mortality in 2015. We finally obtained the PAF for site-specific and total cancers attributable to all modifiable risk factors using this formula, with statistical consideration of the effect of overlap between risk factors. The results showed that 35.9% of all cancer incidence (43.4% in men and 25.3% in women) and 41.0% of all cancer mortality (49.7% in men and 26.8% in women) would be considered preventable by avoidance of these exposures. Infections and active smoking followed by alcohol drinking were the greatest contributing factors to cancer in Japan in 2015.

Population attributable fractions of modifiable cancer risk factors in Korea: a systematic review protocol

INTRODUCTION

The burden of cancer continues to increase worldwide, and cancer is the leading cause of life expectancy reduction and death in Korea. Population attributable fraction (PAF), an epidemiological measure of exposures and health outcomes, could provide information on the public health impacts of exposures in populations. Knowing the PAFs of modifiable risk factors could aid in planning and prioritising strategies to reduce cancer burden in the population. This study aims to summarise systematically the PAF estimates of modifiable cancer risk factors in Korea.

METHODS AND ANALYSIS

This review will include studies that determined PAFs of modifiable risk factors on cancer incidence and mortality in Korea. We will define modifiable risk factors as those that can be changed directly by peoples' conscious actions. We will perform systematic searches in EMBASE, MEDLINE, Cochrane Library and Korean databases (Korean Studies Information Service System, Research Information Sharing Service, KoreaMED, Korean Medical Database, National Assembly Library, and Korea Institute of Science and Technology Information) from their inception to July 2021. Two reviewers will independently screen studies for eligibility, extract data and perform quality assessments of the included studies. We will present the results in a qualitative or descriptive manner and will not perform meta-analyses or other quantitative data synthesis to derive summary estimates of PAFs because we anticipate high variability among PAF estimates.

ETHICS AND DISSEMINATION

Ethics approval is not required because we will only use data from published papers. We will disseminate the results through publication in a peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42021268258.

Population Attributable Fraction of Helicobacter pylori Infection-Related Gastric Cancer in Korea: A Meta-Analysis

PURPOSE

This study aimed to determine the proportion of gastric cancer attributable to Helicobactor pylori in the Korean population. Infection with H. pylori has been recognized as the most significant risk factor for gastric cancer. In Korea, gastric cancer is the most common cancer that accounted for 13.3% of all cancers in 2016. In particular, men are most commonly diagnosed with gastric cancer; the age-standardized incidence rate in men is 49.6 per 100,000, which is more than twice the incidence in women.

MATERIALS AND METHODS

The population attributable fraction (PAF) was calculated as a function of the relative risk (RR) of gastric cancer associated with H. pylori infections. To estimate PAF of gastric cancer due to H. pylori, the prevalence of H. pylori infections was extrapolated for the year of 1990 and a pooled RR was obtained by conducting a meta-analysis of studies recently published in Korea.

RESULTS

The estimated prevalence of H. pylori was 76.4% in men and 71.9% in women. The RRs (95% confidence interval) pooled from case-control studies using a random effects model was 1.69 (1.29-2.22) for overall gastric cancer and 2.17 (1.04-4.55) for non-cardia gastric cancer. Using the RR for overall gastric cancer, the estimated PAFs due to H. pylori were 34.5% in men and 33.2% in women.

CONCLUSION

The occurrence of gastric cancer in Koreans may be affected by other risk factors in addition to H. pylori infection, which may contribute to increasing baseline risk for gastric cancer.

Incidence, cost and gender differences of oropharyngeal and noncervical anogenital cancers in South Korea

Background

Human papillomavirus (HPV) is associated with a significant public health burden, yet few studies have been conducted in Asia, especially on noncervical cancers. We estimated the incidence and cost of oropharyngeal and noncervical anogenital (anal, vulvar, vaginal, penile) cancer in Korea.

Methods

We conducted a retrospective cohort study using Korea’s National Health Insurance (NHI) claim database from 2013 to 2016. The main outcome measures were the number of respective cancer incidences during the study period and the annual costs per patient in the first year after diagnosis, which was adjusted by relevant variables based on the regression analysis.

Results

During the study period, 8022 patients with these cancers were identified, and oropharyngeal cancer comprised 46% of them. The crude incidence rate for male oropharyngeal cancer was significantly higher than that of females (3.1 vs. 0.7 per 100,000 as of 2016, respectively). Additionally, the crude incidence of male oropharyngeal cancer increased from 2.7 in 2013 to 3.1 in 2016, whereas that of female and other cancers was stable during the study period. The mean annual incidence-based cost per patient in 2016 was highest for oropharyngeal cancers (21,870 USD), and it was significantly higher in males than in females based on then regression analysis (p < .001).

Conclusions

Oropharyngeal cancer comprises the highest number of HPV-associated noncervical cancer incidences in Korea, and the incidence and cost of oropharyngeal cancer was significantly higher among males than females. More aggressive public health policy toward males may decrease gender gap of oropharyngeal cancer.

The Economic Burden of Cancers Attributable to Infection in the Republic of Korea: A Prevalence-Based Study

Infection is a major cause of cancers. We estimated the economic burden of cancers attributable to infection in 2014 in Korea, where cancer causing infection is prevalent, but the economic burden of it has never been examined. Cancer patients were defined as those having made medical claims as recorded by the National Health Insurance Service, which is a mandatory insurance for all citizen. We multiplied the costs by the population-attributable fraction for each type of cancer. The study included direct and indirect costs, where direct costs comprised direct medical and non-medical costs of inpatients and outpatients, while indirect costs were estimated by identifying future income loss due to premature death, productivity loss during hospitalization/outpatient visits, and job loss. In 2014, there were 100,054 infection-related cancer patients, accounting for 10.7% of all Korean cancer cases for that year. Direct costs of cancers associated with infection stood at nearly USD 676.9 million, while indirect costs were much higher at USD 2.57 billion. The average expenditure of a typical patient was USD 32,435. Economic burden of cancers attributable to infection is substantial in Korea, accounting for 0.23% of the national gross domestic product and 1.36% of national healthcare expenditure in 2014.

Population Attributable Fraction of Established Modifiable Risk Factors on Colorectal Cancer in Korea

Purpose

We estimated the population attributable fraction (PAF) of established risk factors for colorectal cancer, to provide evidence for prioritizing cancer prevention policy.

Materials and Methods

The exposure prevalence was calculated by using data from the 2005 Korean National Health Examination Survey for tobacco smoking, alcohol consumption, obesity, physical inactivity, and meat intake. Risk estimates (relative risks) were selected from the published meta-analyses. Cancer incidence data from the Korea Central Cancer Registry were used to estimate the preventable number of colorectal cancer cases in 2015.

Results

The PAFs of the tobacco smoking, alcohol consumption, obesity, physical inactivity, and consumption of red and processed meat were as follows: 9.2%, 11.1%, 9.1%, 18.9%, and 10.1% for colon cancer and 21.8%, 12.3%, 3.5%, 5.3%, and 9.2% for rectal cancer among men; 1.0%, 1.3%, 2.7%, 12.3% and 9.2% for colon cancer and 1.7%, 2.3%, 0.8%, 7.2%, and 8.3% for rectal cancer among women. The PAFs of selected risk factors were 46.2% for colon and 42.4% for rectum among men, while 24.3% for colon and 18.9% for rectum among women. The attributable numbers of colon and rectal cancer to selected risk factors were 4,028 and 3,049 cases among men, respectively, while 1,644 and 778 cases among women in the year of 2015.

Conclusion

Changes in modifiable risk factors could prevent half of the colorectal cancer in the Korean population.

ABC Classification Is Less Useful for Older Koreans Born before 1960

Background/Aims

In the ABC classification system, group A consists of seronegative subjects without gastric corpus atrophy. This study aimed to determine the prevalence and characteristics of pseudo group A subjects.

Methods

Group A subjects were identified among consecutive Korean adults who underwent a serum anti-Helicobacter pylori immunoglobulin G (IgG) test and pepsinogen (PG) assay on the day of endoscopy. Past infection was defined as the presence of either eradication history or endoscopic findings suggesting past infection (i.e., gastric xanthoma, metaplastic gastritis, or advanced atrophy >closed-type 1).

Results

Among 2,620 group A subjects, 448 (17.1%) had eradication history, and 133 (5.1%) showed endoscopic findings suggesting past infection. Older age (odds ratio [OR], 1.148; 95% confidence interval [CI], 1.067 to 1.236) and earlier year of birth (OR, 1.086; 95% CI, 1.009 to 1.168) were independent risk factors for classification into pseudo group A, with cutoff points at 50.5 years and birth year of 1959.5, respectively. Positive H. pylori test findings were found in 22 subjects (3.1%) among the 715 subjects who underwent the urea breath test or Giemsa staining on the same day. Current infection was positively correlated with PG I and PG II levels (p<0.001) but not with age, anti-H. pylori IgG titer, or classification into pseudo group A.

Conclusions

Among the group A subjects, 22.2% had past infection. The risk was higher in subjects older than 50 years, especially those born before 1960. Furthermore, current infection was found in 3.1% of the subjects and was correlated with increased gastric secretory ability.

Estimates of the incidence of infection-related cancers in Italy and Italian regions in 2018

Introduction

Chronic infections and infestations represent one of the leading causes of cancer. Eleven agents have been categorized by the International Agency for Research on Cancer (IARC) in Group 1, 3 in Group 2A and 4 in Group 2B. We previously estimated that the incidence of cancers associated with infectious agents accounted for the 8.5% of new cancer cases diagnosed in Italy in 2014.

Methods

In the present study we evaluated the incidence of cancer in Italy and in the 20 Italian regions in 2018, based on the data of Cancer Registries, and calculated the fraction attributable to infectious agents.

Results

Cancers of infectious origin contributed to the overall burden of cancer in Italy with more than 27,000 yearly cases, the 92% of which was attributable to Helicobacter pylori, human papillomaviruses, and hepatitis B and C viruses. With the exception of papillomavirus-related cancers, the incidence of cancers of infectious origin was higher in males (16,000 cases) than in females (11,000 cases). There were regional and geographical variations of cancers depending on the type of cancer and on the gender. Nevertheless, the overall figures were rather similar, the infection-related cancers accounting for the 7.2, 7.6, and 7.1% of all cancers in Northern, Central, and Southern Italy, respectively.

Conclusions

The estimate of the incidence of cancers attributable to infectious agents in Italy in 2018 (7.3% of all cancer cases) is approximately half of the worldwide burden, which has been estimated by IARC to be the 15.4% of all cancer cases in 2012.

De novo cancer incidence after kidney and liver transplantation: Results from a nationwide population based data

The cancer risk among solid organ transplantation recipients in East-Asia has been insufficiently studied. This study estimated de novo cancer incidence in kidney and liver recipients 2008-2015, compared with the general population in Korea using nationwide data. This is a retrospective cohort study using nationwide health insurance claims data. The study population was comprised of cancer-free 10,085 kidney recipients and 3,822 liver recipients. Standardized incidence ratio (SIR) of cancer using indirect standardization was calculated. Compared with the general population, the cancer risk increased by 3.19-fold in male and 2.56-fold in female kidney recipients. By cancer type, a notably increased SIR was observed for Kaposi sarcoma, renal cancer, skin cancer, and non-Hodgkin's lymphoma in male and for bladder cancer, renal cancer, and non-Hodgkin's lymphoma in female kidney recipients. In liver recipients, the SIR of all cancers was 3.43 in males and 2.30 in females. In male liver recipients, the SIRs for Kaposi sarcoma, non-Hodgkin's lymphoma, myeloid leukemia, and skin cancer and in female recipients those for non-Hodgkin's lymphoma and liver cancer were prominent. A greatly higher SIRs for overall cancer and non-Hodgkin's lymphoma in kidney and liver recipients aged 0-19 were observed, compared with recipients in other age group. The incidence of de novo cancer in kidney and liver recipients was higher than the general population and common types were different. Strategies of cancer prevention and screening after kidney and liver transplantation should be developed in response to the incidence of common types of de novo cancers.

Prevalence of human papillomavirus-related diseases in the Republic of Korea: a cross-sectional study

OBJECTIVE

We aimed to evaluate trends in the prevalence of human papillomavirus (HPV)-related diseases in the era before the introduction of organised HPV vaccination programmes in the Republic of Korea.

METHODS

This cross-sectional study used National Health Insurance Service data from 2002 to 2015 and included participants who were diagnosed with the following HPV-related diseases (codes from the International Classification of Diseases, 10th Revision): genital warts (A63.0); cancer in the head and neck (C00-C10), anus (C21), vulva (C51), vagina (C52), cervix uteri (C53) and penis (C60); carcinoma in situ (CIS) of the lip/oral cavity/pharynx (D00.0), anus (D01.3), cervix (D06), vulva (D07.1), vagina (D07.2) and penis (D07.4); benign neoplasms of the larynx (D14.1); and dysplasia of the cervix (N87), vagina (N89) and vulva (N90). For each diagnosis, the fraction of cases attributable to HPV in Korea was assessed based on the percentages of diseases attributable to HPV reported in some international studies. The age-standardised prevalence was estimated using the direct population-based method.

RESULTS

The overall age-standardised prevalence of HPV-related diseases increased from 2002 to 2015, mainly due to increased prevalence of genital warts in men and cervical dysplasia and CIS in women. In women, genital wart prevalence increased from 2002 (24.4 per 100 000) to 2011 (57.1) and then decreased until 2015 (53.5); in men, the prevalence increased steadily from 2002 (22.9) to 2015 (109.4). The prevalence of cervical dysplasia and CIS increased (from 86.5 in 2002 to 484.5 in 2015, and from 60.3 in 2002 to 114.9 in 2015, respectively), but that of cervical cancer decreased (from 120.0 in 2002 to 106.9 in 2015).

CONCLUSIONS

Non-organised HPV vaccination and organised cervical cancer screening may have contributed to the downward trend in genital wart prevalence and the upward trend in cervical abnormalities among women.

Burden of Human papillomavirus (HPV)-related disease and potential impact of HPV vaccines in the Republic of Korea

Background

We aimed to review the burden and the potential impact of human papillomavirus (HPV) vaccines on HPV-related diseases in the Republic of Korea and to discuss cervical cancer prevention practices in this country.

Methods

Cancer burden statistics were retrieved from GLOBOCAN-2018 and Statistics Korea. HPV disease burden was assessed via systematic review. Vaccine types relative contribution (RC) was estimated using data from an international project using formalin-fixed paraffin-embedded specimens.

Results

Despite a downtrend in cervical cancer in recent years, Korean rates remain high. In contrast, oropharyngeal cancer incidence has gradually increased and other anogenital cancers remain rare.

In Korea, HPV prevalence in general population is around 20%. In cervical cancer, RC of HPVs 16/18 (74.0%) increased to 92.0% when including HPVs 31/33/45/52/58. Limited information was available for other HPV-related cancer sites.

Regarding prevention, since the inclusion of the HPV vaccine into the National Immunization Program, almost half (49%) of the target cohort in 2016 had received the first dose of vaccine. Further, percentage of women screened with pap has increased from 41.1%-2009 to 53.0%-2016.

Conclusions

HPV-related disease burden in Korea is significant. Results suggest that the combination of effective and high coverage HPV vaccination and screening programmes could substantially impact on HPV-related disease in Korea.

•

HPV-related disease burden (cancer and genital warts) in Korea is significant.

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HPV16 is the most frequent genotype, causing itself more than 60% of HPV-related cancers.

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HPV vaccine types 16/18/31/33/45/52/58/6/11 cause 92.0% of cervical cancers.

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HPV vaccines could significantly impact on the HPV-related disease burden.

Updates on Cancer Epidemiology in Korea, 2018

Cancer is a major cause of morbidity and the most common cause of death in Korea. There are currently approximately 200,000 incident cancer cases and 78,000 individuals die from cancer every year. The factors directly related to cancer incidence, including aging, smoking, obesity, and Westernized dietary habits, have been increasing during the past several decades. Since 1999, trends toward increased incidence have been observed for thyroid, breast (in women), colorectal, and prostate cancer. Currently, these trends have changed direction, and the incidence of stomach and liver cancer in both sexes, and cervical cancer in women have continually declined. Although the number of cancer deaths increased by a factor of 2.7 from 1983 to 2016, the age-standardized mortality associated with cancer has been decreasing by 3% every year. The 5-year relative survival rate (RSR) has also improved over the past several decades, especially for stomach, prostate, and breast cancer, which had 5-year RSRs greater than 90% in the most recent report.

Patterns and Trends of Liver Cancer Incidence Rates in Eastern and Southeastern Asian Countries (1983-2007) and Predictions to 2030

BACKGROUND & AIMS

We examined temporal trends in liver cancer incidence rates overall and by histological type from 1983 through 2007. We predict trends in liver cancer incidence rates through 2030 for selected Eastern and Southeastern Asian countries.

METHODS

Data on yearly liver cancer incident cases by age group and sex were drawn from 6 major selected Eastern and Southeastern Asian countries or regions with cancer registries available in the CI5plus database, including China, Japan, Hong Kong Special Administrative Region (SAR), the Philippines, Singapore, and Thailand. We also analyzed data for the United States and Australia for comparative purposes. Age-standardized incidence rates were calculated and plotted from 1983 through 2007. Numbers of new cases and incidence rates were predicted through 2030 by fitting and extrapolating age-period-cohort models.

RESULTS

The incidence rates of liver cancer have been decreasing, and decreases will continue in all selected Eastern and Southeastern Asian countries, except for Thailand, whose liver cancer incidence rate will increase due to the increasing incidence rate of intrahepatic cholangiocarcinomas. Even though the incidence rates of liver cancer are predicted to decrease in most Eastern and Southeastern Asian countries, the burden, in terms of new cases, will continue to increase because of population growth and aging.

CONCLUSIONS

Based on an analysis of data from cancer registries from Asian countries, incidence rates of liver cancer are expected to decrease through 2030 in most Eastern and Southeastern Asian countries. However, in Thailand, the incidence rate of intrahepatic cholangiocarcinomas is predicted to increase, so health education programs are necessary.

Validity of self-reported cancer history in the health examinees (HEXA) study: A comparison of self-report and cancer registry records

PURPOSE

To assess the validity of the cohort study participants' self-reported cancer history via data linkage to a cancer registry database.

METHODS

We included 143,965 participants from the Health Examinees (HEXA) study recruited between 2004 and 2013 who gave informed consent for record linkage to the Korean Central Cancer Registry (KCCR). The sensitivity and the positive predictive value of self-reported histories of cancer were calculated and 95% confidence intervals were estimated.

RESULTS

A total of 4,860 participants who had at least one record in the KCCR were included in the calculation of sensitivity. In addition, 3,671 participants who reported a cancer history at enrollment were included in the calculation of positive predictive value. The overall sensitivity of self-reported cancer history was 72.0%. Breast cancer history among women showed the highest sensitivity (81.2%), whereas the lowest sensitivity was observed for liver cancer (53.7%) and cervical cancer (52.1%). The overall positive predictive value was 81.9%. The highest positive predictive value was observed for thyroid cancer (96.1%) and prostate cancer (96.1%), and the lowest was observed for cervical cancer (43.7%).

CONCLUSION

The accuracy of self-reported cancer history varied by cancer site and may not be sufficient to ascertain cancer incidence, especially for cervical and bladder cancers.

Burden of Cancers Attributable to Infectious Agents in Nigeria: 2012-2014

Introduction

Infections by certain viruses, bacteria, and parasites have been identified as risk factors for some cancers. In Nigeria, like many other developing countries, infections remain a leading cause of morbidity and mortality. While there are data on the incidence of different cancers in Nigeria, there has been no study of cancers attributable to infections. This study was carried out to determine the burden of cancers attributable to infections using data from two population-based cancer registries (PBCRs) in Nigeria.

Methods

We obtained data on cancers associated with EBV, human papillomavirus (HPV), hepatitis B and C, HIV, HHV8, Helicobacter pylori, and Schistosoma spp. from the databases of Abuja and Enugu cancer registries in Nigeria. We used population-attributable fraction for infections-associated cancers in developing countries that are based on prevalence data and relative risk estimates from previous studies.

Results

The PBCRs reported 4,336 incident cancer cases [age standardized incidence rate (ASR) 113.9 per 100,000] from 2012 to 2014, of which 1,627 (37.5%) were in males and 2,709 (62.5%) were in females. Some 1,030 (23.8%) of these cancers were associated with infections (ASR 44.4 per 100,000), while 951 (22.0%) were attributable to infections (ASR 41.6 per 100,000). Cancers of the cervix (n = 392, ASR 28.3 per 100,000) and liver (n = 145, ASR 3.4 per 100,000); and non-Hodgkin’s lymphoma (n = 110, ASR 2.5 per 100,000) were the commonest infections-associated cancers overall. The commonest infectious agents associated with cancers in this population were HPV, EBV, hepatitis B and C, HIV, and HHV8.

Conclusion

Our results suggest that 23.8% of incident cancer cases in this population were associated with infections, while 22.0% were attributable to infections. The infections attributable cancers are potentially preventable with strategies, such as vaccination, risk factor modification, or anti-infective treatment.

Additive interactions between PRKAA1 polymorphisms and Helicobacter pylori CagA infection associated with gastric cancer risk in Koreans

Although several studies reported genetic polymorphisms in protein kinase AMP‐activated alpha 1 catalytic subunit (PRKAA1) and their associations with gastric cancer risk, few have evaluated associations between Helicobacter pylori infection and PRKAA1 gene‐environment interactions. Here, we evaluated the effects of interactions between H. pylori infection and PRKAA1 polymorphisms on gastric cancer risk in Koreans. In this hospital‐based case–control study, PRKAA1 genotypes were analyzed and H. pylori infection and CagA status were examined using a serologic method in 846 pairs of gastric cancer patients and controls matched for age and sex. H. pylori seropositivity was associated with a 1.43‐fold [95% confidence interval: 1.12–1.81] increase in the risk of gastric cancer, and CagA low‐positive titers during H. pylori infection increased the risk by 1.85‐fold (95% confidence interval, 1.38–2.48). Significant positive interaction between the PRKAA1 rs13361707 genotype and H. pylori infection was verified on an additive scale [relative excess risk due to interaction, 0.55; 95% confidence interval, 0.05–1.04; P = 0.030], and the gene‐environment interaction between PRKAA1 rs13361707 and CagA status was also statistically significant (relative excess risk due to interaction, 0.50; 95% confidence interval, 0.30–0.70; P < 0.001). Our results indicated that H. pylori infection, CagA status, and PRKAA1 polymorphisms were risk factors for gastric cancer in Koreans, and that the combination of two of these factors rather than their independent effects synergistically increased the risk.

Health Screening among HBV Carriers in the Korean National Health and Nutrition Examination Survey V (KNHANES V)

We aimed to investigate the differences in health screening, including medical checkups and cancer screening, between HBV carriers and non-carriers in the Republic of Korea. In the fifth Korean National Health and Nutrition Examination Survey (KNHANES V), conducted between 2010 and 2012, 17,865 persons who answered regarding their HBV-infection status, medical checkup history, liver cancer screening and general cancer screening within the past years were included in the final analysis. In total, 295 persons were HBV carriers. Logistic regression models were used to compare the health check-up rate between the HBV carriers and non- HBV carriers. The HBV carriers were more likely to have been screened for liver cancer [adjusted odds ratio (OR): 2.83, 95% confidence interval (95%CI): 1.90-4.21] or cancer [OR: 1.44, 95%CI: 1.04-1.99]. The HBV carriers showed a probability of receiving medical checkups that was identical to that of the non-carriers [OR: 0.99, 95%CI: 0.72-1.35]. The HBV carriers, who were at higher risk of developing chronic liver disease, were more likely to be screened for cancer, including liver cancer, than the non-HBV carriers; no difference in the rate of medical checkups was observed between the HBV carriers and non-HBV carriers.

The Fraction of Cancer Attributable to Ways of Life, Infections, Occupation, and Environmental Agents in Brazil in 2020

Many human cancers develop as a result of exposure to risk factors related to the environment and ways of life. The aim of this study was to estimate attributable fractions of 25 types of cancers resulting from exposure to modifiable risk factors in Brazil. The prevalence of exposure to selected risk factors among adults was obtained from population-based surveys conducted from 2000 to 2008. Risk estimates were based on data drawn from meta-analyses or large, high quality studies. Population-attributable fractions (PAF) for a combination of risk factors, as well as the number of preventable deaths and cancer cases, were calculated for 2020. The known preventable risk factors studied will account for 34% of cancer cases among men and 35% among women in 2020, and for 46% and 39% deaths, respectively. The highest attributable fractions were estimated for tobacco smoking, infections, low consumption of fruits and vegetables, excess weight, reproductive factors, and physical inactivity. This is the first study to systematically estimate the fraction of cancer attributable to potentially modifiable risk factors in Brazil. Strategies for primary prevention of tobacco smoking and control of infection and the promotion of a healthy diet and physical activity should be the main priorities in policies for cancer prevention in the country.

Population attributable risks of modifiable reproductive factors for breast and ovarian cancers in Korea

Background

Breast and ovarian cancers are predominant female cancers with increasing prevalence. The purpose of this study was to estimate the population attributable risks (PARs) of breast and ovarian cancer occurrence based on the relative risks (RRs) of modifiable reproductive factors and population-specific exposure prevalence.

Methods

The PAR was calculated by using the 1990 standardized prevalence rates, the 2010 national cancer incidence with a 20 year lag period, the meta-analyzed RRs from studies conducted in the Korean population for breast cancer, and the meta-analyzed RRs from a Korean epithelial ovarian cancer study and a prior meta-analysis, and ovarian cancer cohort results up to 2012. For oral contraceptive and hormone replacement therapy use, we did not consider lag period.

Results

The summary PARs for modifiable reproductive factors were 16.7 % (95 % CI 15.8–17.6) for breast cancer (2404 cases) and 81.9 % (95 % CI 55.0–100.0) for ovarian cancer (1579 cases). The modifiable reproductive factors included pregnancy/age at first birth (8.0 %), total period of breastfeeding (3.1 %), oral contraceptive use (5.3 %), and hormone replacement therapy use (0.3 %) for breast cancer and included breastfeeding experience (2.9 %), pregnancy (1.2 %), tubal ligation (24.5 %), and oral contraceptive use (53.3 %) for ovarian cancer.

Conclusions

Despite inherent uncertainties in the risk factors for breast and ovarian cancers, we suggest that appropriate long-term control of modifiable reproductive factors could reduce breast and ovarian cancer incidences and their related burdens by 16.7 % and 81.9 %, respectively.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-2040-0) contains supplementary material, which is available to authorized users.

Infection and cancer: global distribution and burden of diseases

BACKGROUND

Infection is one of the main risk factors for cancer.

OBJECTIVES

Epidemiology, pathogenesis, and disease burden of infection-related cancers were reviewed by infectious agents.

FINDINGS

Chronic infection with Epstein-Barr virus, hepatitis B and C viruses, Kaposi sarcoma herpes virus, human immunodeficiency virus (HIV) type 1, human papillomavirus (HPV), human T-cell lymphotropic virus type 1, Helicobacter pylori, Clonorchis sinensis, Opisthorchis viverrini, and Schistosoma haematobium are associated with nasopharyngeal carcinoma; lymphoma and leukemia, including non-Hodgkin lymphoma, Hodgkin lymphoma, and Burkitt lymphoma; hepatocellular carcinoma; Kaposi sarcoma; oropharyngeal carcinoma; cervical carcinoma and carcinoma of other anogential sites; adult T-cell leukemia/lymphoma; gastric carcinoma; cholangiocarcinoma; and urinary bladder cancer. In 2008, approximately 2 million new cancer cases (16%) worldwide were attributable to infection. If these infections could be prevented and/or treated, it is estimated that there would be about 23% fewer cancers in less developed regions of the world, and about 7% fewer cancers in more developed regions.

CONCLUSION

Widespread application of existing public health methods for the prevention of infection, such as vaccination, safer injection practices, quality-assured screening of all donated blood and blood components, antimicrobial treatments, and safer sex practices, including minimizing one's lifetime number of sexual partners and condom use, could have a substantial effect on the future burden of cancer worldwide.

Ten-Year Changes in the Hepatitis B Prevalence in the Birth Cohorts in Korea: Results From Nationally Representative Cross-Sectional Surveys

To compare the prevalence of hepatitis B virus (HBV) infection over a 10-year period in terms of population-level trends, we established hypothetical birth cohorts that represented each 10-year interval age group.We used data from the Korean National Health and Nutrition Examination Surveys conducted between 1998 to 2001 and 2008 to 2011. Trends in the HBV infection were calculated using data from individuals aged 20 to 59 years in 1998 to 2001 and those aged 30 to 69 years in 2008 to 2011.In 2008 to 2011, the prevalence of HBV infection, as measured using serum HBV surface antigen (HBsAg) seroprevalence, among participants aged 30 to 69 years was 4.2% (95% CI = 3.7-4.7%), which represents a 1.3% absolute change and 20% change in prevalence ratio, which was significant compared with the prevalence among those aged 20 to 59 years in 1998 to 2001 (5.5%, 95% CI = 4.7-6.3%). The prevalence of HBV infection decreased most in the lowest income group, with marginal significance in males (P = 0.06) and significance in females (P = 0.03). In terms of education, females with at least a high school education showed a significant decrease (P = 0.03).Using a birth cohort approach, the prognosis for HBV infection in terms of death or hospitalization, or resolution upon antiviral treatment of their HBV infections, identified by a decrease in the HBsAg seroprevalence was worse in the lower income group and in females with higher education. We postulate that these socioeconomic inequalities were caused by alcohol consumption, disparities in liver cancer surveillance, and access to antiviral treatment because of cost and reimbursement guidelines.

Estimation of Cancer Burden Attributable to Infection in Asia

BACKGROUND

Some infectious agents have been shown to be human carcinogens. The current study focused on estimation of cancer burden attributable to infection in different regions of Asia.

METHODS

By systematically reviewing previous studies of the infection prevalence data of 13 countries in Asia and relative risks of specific cancers, we calculated the population attributable fraction of carcinogenic infections. Using data from GLOBOCAN 2012, the overall country-specific and gender-specific number of new cancer cases and deaths resulting from infection were estimated.

RESULTS

Across 13 principal Asian countries, the average prevalence and range was 6.6% (0.5% in Japanese women to 15.0% in Vietnamese men) for hepatitis B virus (HBV), 2.6% (0.3% in Iran to 5.1% in Saudi Arabia) for hepatitis C virus (HCV), 7.9% (2.8% in Pakistan to 17.7% in China) for human papillomavirus (HPV), and 61.8% (12.8% in Indonesia to 91.7% in Bangladesh) for Helicobacter pylori (HP). The estimated total number of cancer cases and deaths caused by infection in these 13 countries were 1 212 026 (19.6% of all new cancer cases) and 908 549 (22.0% of all deaths from cancer). The fractions of cancer incidence attributable to infection were 19.7% and 19.5% in men and women, respectively. The percentages of cancer deaths attributable to infection were 21.9% and 22.1% in men and women, respectively. Among the main infectious agents, HP was responsible for 31.5% of infection-related cancer cases and 32.8% of infection-related cancer deaths, followed by HBV (28.6% of new cases and 23.8% of deaths), HPV (22.0% of new cases and 27.3% of deaths), and HCV (12.2% of new cases and 10.6% of deaths).

CONCLUSIONS

Approximately one quarter of all cancer cases and deaths were infection-associated in Asia, which could be effectively prevented if appropriate long-term controls of infectious agents were applied.

The Economic Burden of Cancers Attributable to Metabolic Syndrome in Korea

OBJECTIVES

Metabolic syndrome is an important etiologic factor in the development of certain types of cancers. The economic cost of the treatment of cancer has been steadily increasing. We therefore estimated the economic burden of cancers attributable to metabolic syndrome in Korea.

METHODS

We reviewed metabolic syndrome-related cancers and relative risk and then calculated population attributable fractions. We analyzed insurance claims data for metabolic syndrome-related cancers in 2012 in order to estimate the direct costs associated with these cancers, including hospitalization, outpatient visits, transportation costs, and caregivers' costs as well as indirect costs such as loss of productivity due to cancer treatment and premature death.

RESULTS

In 2012, 18,070 patients in Korea had cancers attributable to metabolic syndrome. The economic burden was USD 199.8 million and the direct and indirect costs were USD 124.5 million and USD 75.3 million, respectively.

CONCLUSIONS

We estimated the economic burden of cancers attributable to metabolic syndrome in Korea and the efforts are necessary to reduce this burden.

The Economic Burden of Hepatitis A, B, and C in South Korea

The prevalence of hepatitis in South Korea is relatively high compared to that in other high-income countries. For this reason, viral hepatitis infection not only affects the population's health, but also impacts national healthcare costs. This study was performed in order to estimate the individual economic costs of the hepatitis A, B, and C viruses as well as to determine, using nationally representative data, the trends in South Korea with respect to these viruses during the 2008-2011 period. The study found that the prevalence of hepatitis A had decreased, but those of hepatitis B and C had increased overall. The mortality rate of hepatitis C was higher than that of the other two types. The mortality rate of hepatitis B had changed little, whereas that of hepatitis C had risen. The total cost of hepatitis A had decreased, from US $62.2 million to US $45.7 million, although a notable exception occurred in 2009, when the cost was US $126.6 million. Conversely, the total cost of hepatitis B had increased rapidly during the same period, from US $501.4 million to US $607.8 million. Finally, the total cost of hepatitis C had also increased from US $63.9 million to US $90.7 million. The direct costs of hepatitis A, B, and C were estimated to account for approximately 35.5%, 46.6%, and 58.0% of the total, respectively. These findings demonstrate the economic burden associated with hepatitis A, B, and C, and demonstrate the need to establish an effective prevention and management policy for future planning in South Korea.

Viral hepatitis and liver cancer in Korea: an epidemiological perspective

In the past, hepatitis B virus (HBV) infection was endemic in the general Korean population. The association of HBV infection with the occurrence of liver cancer has been well demonstrated in several epidemiologic studies. While the mortality rates of liver cancer in Korea have decreased steadily over the last decade, the presence of hepatitis B surface antigen (HBsAg) in mothers remains high at 3-4%, and 25.5% of these HBsAg positive mothers are positive for hepatitis B e antigen (HBeAg). HBV infection caused almost a quarter of hepatocellular carcinoma (HCC) cases and one-third of deaths from HCC. These aspects of HBV infection prompted the Korean government to create a vaccination program against HBV in the early 1980s. In 1995, the Communicable Disease Prevention Act (CDPA) was reformed, and the government increased the number of HBV vaccines in the National Immunization Program (NIP), driving the vaccination rate up to 95%. In 2000, the National Health Insurance Act (NHIA) was enacted, which provided increased resources for the prevention of perinatal HBV infection. Then in 2002, the Korean government, in conjunction with the Korean Medical Association (KMA), launched an HBV perinatal transmission prevention program. The prevalence of HBsAg in children had been high (4-5%) in the early 1980s, but had dropped to below 1% in 1995, and finally reached 0.2% in 2006 after the NIP had been implemented. After the success of the NIP, Korea finally obtained its first certification of achievement from the Western Pacific Regional Office of the World Health Organization (WPRO-WHO) for reaching its goal for HBV control. An age-period-cohort analysis showed a significant reduction in the liver cancer mortality rate in children and adolescents after the NIP had been implemented. In addition to its vaccination efforts, Korea launched the National Cancer Screening Program (NCSP) for 5 leading sites of cancer, including the liver, in 1999. As a consequence of this program, the 5-year liver cancer survival rate increased from 13.2% (1996-2000) to 23.3% (2003-2008). The development of both the primary and secondary prevention for liver cancer including HBV immunization and cancer screening has been of critical importance.

Attributable causes of liver cancer mortality and incidence in china

OBJECTIVES

To estimate the proportion of liver cancer cases and deaths due to infection with hepatitis B virus (HBV), hepatitis C virus (HCV), aflatoxin exposure, alcohol drinking and smoking in China in 2005.

STUDY DESIGN

Systemic assessment of the burden of five modifiable risk factors on the occurrence of liver cancer in China using the population attributable fraction.

METHODS

We estimated the population attributable fraction of liver cancer caused by five modifiable risk factors using the prevalence data around 1990 and data on relative risks from meta-analyses, and large-scale observational studies. Liver cancer mortality data were from the 3rd National Death Causes Survey, and data on liver cancer incidence were estimated from the mortality data from cancer registries in China and a mortality/incidence ratio calculated.

RESULTS

We estimated that HBV infection was responsible for 65.9% of liver cancer deaths in men and 58.4% in women, while HCV was responsible for 27.3% and 28.6% respectively. The fraction of liver cancer deaths attributable to aflatoxin was estimated to be 25.0% for both men and women. Alcohol drinking was responsible for 23.4% of liver cancer deaths in men and 2.2% in women. Smoking was responsible for 18.7% and 1.0% . Overall, 86% of liver cancer mortality and incidence (88% in men and 78% in women) was attributable to these five modifiable risk factors.

CONCLUSIONS

HBV, HCV, aflatoxin, alcohol drinking and tobacco smoking were responsible for 86% of liver cancer mortality and incidence in China in 2005. Our findings provide useful data for developing guidelines for liver cancer prevention and control in China and other developing countries.

Setting a health policy research agenda for controlling cancer burden in Korea

Purpose

The aim of study was to provide suggestions for prioritizing research in effort to reduce cancer burden in Korea based on a comprehensive analysis of cancer burden and Delphi consensus among cancer experts.

Materials and Methods

Twenty research plans covering 10 topics were selected based on an assessment of the literature, and e-mail surveys were analyzed using a two-round modified Delphi method. Thirty-four out of 79 experts were selected from four organizations to participate in round one, and 21 experts among them had completed round two. Each item had two questions; one regarding the agreement of the topic as a priority item to reduce cancer burden, and the other about the importance of the item on a nine-point scale. A consensus was defined to be an average lower coefficient of variation with less than 30% in importance.

Results

Seven plans that satisfied the three criteria were selected as priority research plans for reducing cancer burden. These plans are “research into advanced clinical guidelines for thyroid cancer given the current issue with over-diagnosis,” “research into smoking management plans through price and non-price cigarette policy initiatives,” “research into ways to measure the quality of cancer care,” “research on policy development to expand hospice care,” “research into the spread and management of Helicobacter pylori,” “research on palliative care in a clinical setting,” and “research into alternative mammography methods to increase the accuracy of breast cancer screenings.”

Conclusion

The seven plans identified in this study should be prioritized to reduce the burden of cancer in Korea. We suggest that policy makers and administrators study and invest significant effort in these plans.

Cancer control programs in East Asia: evidence from the international literature

Cancer is a major cause of mortality and morbidity throughout the world, including the countries of North-East and South-East Asia. Assessment of burden through cancer registration, determination of risk and protective factors, early detection and screening, clinical practice, interventions for example in vaccination, tobacco cessation efforts and palliative care all should be included in comprehensive cancer control programs. The degree to which this is possible naturally depends on the resources available at local, national and international levels. The present review concerns elements of cancer control programs established in China, Taiwan, Korea, and Japan in North-East Asia, Viet Nam, Thailand, Malaysia, and Indonesia as representative larger countries of South-East Asia for comparison, using the published literature as a guide. While major advances have been made, there are still areas which need more attention, especially in South-East Asia, and international cooperation is essential if standard guidelines are to be generated to allow effective cancer control efforts throughout the Far East.

Cancer is a major cause of mortality and morbidity throughout the world, including the countries of North-East and South-East Asia. Assessment of burden through cancer registration, determination of risk and protective factors, early detection and screening, clinical practice, interventions for example in vaccination, tobacco cessation efforts and palliative care all should be included in comprehensive cancer control programs. The degree to which this is possible naturally depends on the resources available at local, national and international levels. The present review concerns elements of cancer control programs established in China, Taiwan, Korea, and Japan in North-East Asia, Viet Nam, Thailand, Malaysia, and Indonesia as representative larger countries of South-East Asia for comparison, using the published literature as a guide. While major advances have been made, there are still areas which need more attention, especially in South-East Asia, and international cooperation is essential if standard guidelines are to be generated to allow effective cancer control efforts throughout the Far East.

Necessity for a national carcinogen list in Korea, based on international harmonization

Cancer has been the leading cause of death in Korea for the last 30 years. Cancer patients' 5-year survival rate between 2005 and 2009 was 62.0%, representing a highly advanced standard of care, as much as developed countries in the EU and the US. The Korean government formulated its first 10-year plan for cancer control in 1996 and has been carrying out a second 10-year plan for cancer control since 2006. But despite the Korean government's efforts, the cancer burden in Korea continues to increase. Many separate laws have gone into effect concerning the management of carcinogen exposure. However, there are no integrated regulatory laws or management systems against carcinogen exposure in Korea. Dead zones remain where carcinogen exposure cannot be controlled properly in Korea. In this paper, we suggest the need to establish a national carcinogen list based on international harmonization as a prerequisite for a paradigm shift in cancer control policy from treatment to primary prevention.

Determinants of suboptimal hepatitis B vaccine uptake among men in the Republic of Korea: where should our efforts be focused: results from cross-sectional study

Background

Liver cancer is the second most-frequent cause of cancer death in Korea. Hepatitis B virus (HBV) infection is a major cause of liver cancer, and this disease is effectively prevented by HBV vaccination. This study was conducted to investigate factors associated with the lack of HBV vaccine uptake in the general adult male population in Korea.

Methods

Data of men who participated in a nationwide cross-sectional interview survey were analyzed. A total of 2,174 men 40 years of age and older were interviewed between 2006 and 2008. None of the participants was infected with HBV or was experiencing sequelae of an HBV infection.

Results

Only half (50.4%) of the men received one or more dose of the three-dose series of HBV vaccinations, and 32.5% received all three doses. Compared with men who had completed the vaccination regimen, non-vaccinated men were more likely to lack supplemental medical insurance for cancer (odds ratio = 0.66, 95% confidence interval: 0.52–0.84), have lower incomes (p-trend = 0.010), and be less educated (p-trend = 0.021). Lower education was also more prevalent in the non-vaccinated group compared with the incompletely vaccinated group. Those who had completed the vaccination regimen were likely to be more educated than those in the incompletely vaccinated group (p-trend = 0.044). The most commonly cited reason for not obtaining the HBV vaccine was lack of knowledge regarding the need for the vaccination. The number of men who cited this reason decreased as a function of education.

Conclusions

It is important to develop strategic interventions targeted at less-educated men to increase uptake of a complete three-dose series of HBV vaccinations as a primary approach to preventing liver cancer.

A novel multiplex real-time PCR assay for the concurrent detection of hepatitis A, B and C viruses in patients with acute hepatitis

A novel multiplex real-time PCR assay for concurrent detection of hepatitis viruses was evaluated for its clinical performance in screening patients with acute hepatitis. A total of 648 serum samples were collected from patients with acute symptoms of hepatitis. Concurrent detection of nucleic acids of HAV, HBV and HCV was performed using the Magicplex™ HepaTrio Real-time Detection test. Serum nucleic acid levels of HBV and HCV were also quantified by the Cobas® AmpliPrep/Cobas® TaqMan® (CAP/CTM) HBV and HCV tests. Patients’ medical records were also reviewed. Concordance rates between the results from the HepaTrio and the CAP/CTM tests for the detection of HBV and HCV were 94.9% (k = 0.88) and 99.2% (k = 0.98), respectively. The cycle threshold values with the HepaTrio test were also correlated well with the levels of HBV DNA (r = −0.9230) and HCV RNA (r = −0.8458). The sensitivity and specificity of the HepaTrio test were 93.8% and 98.2%, respectively, for detecting HBV infection, and 99.1% and 100.0%, respectively, for HCV infection. For the HepaTrio test, 21 (3.2%) cases were positive for both HBV and HCV. Among the positive cases, 6 (0.9%) were true coinfections. This test also detected 18 (2.8%) HAV positives. The HepaTrio test demonstrated good clinical performance and produced results that agreed well with those of the CAP/CTM assays, especially for the detection of HCV. This assay was also able to detect HAV RNA from anti-HAV IgM-positive individuals. Therefore, this new multiplex PCR assay could be useful for the concurrent detection of the three hepatitis viruses.

Attributable causes of cancer in China

BACKGROUND

Most cancers are due to modifiable lifestyle and environmental risk factors, and are potentially preventable. No studies have provided a systematic quantitative assessment of the burden of cancer mortality and incidence attributable to known risk factors in China.

METHODS

We calculated the proportions of cancer deaths and new cases attributable to known risk factors in China, based on the prevalence of exposure around 1990 and national data on cancer mortality and incidence for the year 2005.

RESULTS

Chronic infection is the main risk factor for cancer in China, accounting for 29.4% of cancer deaths (31.7% in men and 25.3% in women), followed by tobacco smoking (22.6% with 32.7% in men and 5.0% in women), low fruit intake (13.0%), alcohol drinking (4.4%), low vegetable intake (3.6%) and occupational exposures (2.7%). The remaining factors, including environmental agents, physical inactivity, the use of exogenous hormones and reproductive factors are each responsible for <1.0%.

CONCLUSIONS

Modifiable risk factors explain nearly 60% of cancer deaths in China, with a predominant role of chronic infection and tobacco smoking. Our findings could provide a basis for cancer prevention and control programs aimed at reducing cancer risk in other developing countries.

Multiplicative synergistic risk of hepatocellular carcinoma development among hepatitis B and C co-infected subjects in HBV endemic area: a community-based cohort study

Background

There has been limited study on the effect of infection with different hepatitis C virus (HCV) genotypes on the risk of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) endemic regions of Asia.

Methods

Hazard ratios of HCC development were estimated for HBV and HCV co-infected subjects among a community-based prospective cohort. HCV genotype was determined in HCV RNA-positive samples. Incident HCC cases were identified through linkage to the cancer registry.

Results

HCC incidence was 79 per 100,000 person-years in the study population (50 incident cases among 6,694 individuals within 63,170 person-years with an average of 9.4 years of follow-up); seroprevalence of HBsAg and anti-HCV was 5.2% and 5.6%. Adjusted hazard ratios of HCC by HBsAg positivity and anti-HCV positivity were 13.3 (CI: 7.3-24.4) and 6.7 (CI: 3.6-12.6). HRs of HBV and HCV monoinfection, and HBV/HCV coinfection were 17.1 (CI: 8.4-34.8), 10.4 (CI: 4.9-22.1) and 115.0 (CI: 32.5-407.3). Multiplicative synergistic effect of HBV/HCV coinfection on HCC risk was also observed (synergy index: 4.5, CI: 1.3-15.5). Infection with HCV genotype 1 (HR: 29.7, CI: 13.6-46.8) and mixed infection with genotype 1 and 2 (HR: 68.7, CI: 16.4-288.4) significantly elevated HCC risk, much higher than HBV infection.

Conclusions

The effect of differences in HCV genotype and the multiplicative synergistic effect of HBV/HCV coinfection on HCC risk shown in the present study underline the need for comprehensive identification of hepatitis infection status in order to prevent and control HCC in this HBV endemic area.

Attributable causes of cancer in Japan in 2005--systematic assessment to estimate current burden of cancer attributable to known preventable risk factors in Japan

BACKGROUND

To contribute to evidence-based policy decision making for national cancer control, we conducted a systematic assessment to estimate the current burden of cancer attributable to known preventable risk factors in Japan in 2005.

METHODS

We first estimated the population attributable fractions (PAFs) of each cancer attributable to known risk factors from relative risks derived primarily from Japanese pooled analyses and large-scale cohort studies and the prevalence of exposure in the period around 1990. Using nationwide vital statistics records and incidence estimates, we then estimated the attributable cancer incidence and mortality in 2005.

RESULTS

In 2005, ≈ 55% of cancer among men was attributable to preventable risk factors in Japan. The corresponding figure was lower among women, but preventable risk factors still accounted for nearly 30% of cancer. In men, tobacco smoking had the highest PAF (30% for incidence and 35% for mortality, respectively) followed by infectious agents (23% and 23%). In women, in contrast, infectious agents had the highest PAF (18% and 19% for incidence and mortality, respectively) followed by tobacco smoking (6% and 8%).

CONCLUSIONS

In Japan, tobacco smoking and infections are major causes of cancer. Further control of these factors will contribute to substantial reductions in cancer incidence and mortality in Japan.

Future candidates for indications of Helicobacter pylori eradication: do the indications need to be revised?

Since the discovery of Helicobacter pylori in 1982, the development of several treatment guidelines has allowed a consensus on the indications for H. pylori eradication. Beyond these currently accepted indications, including various upper gastrointestinal disorders and extragastric diseases, a significant amount of new information regarding H. pylori eradication is emerging. Certain types of acute gastritis, such as nodular gastritis, hypertrophic gastritis, Ménétrier's disease, hemorrhagic gastritis, and granulomatous gastritis are reversible after H. pylori eradication. Further, for chronic gastritis, closed-type atrophic gastritis and complete-type intestinal metaplasia appear to be more reversible after H. pylori eradication than open-type atrophic gastritis and incomplete-type intestinal metaplasia. Eradication can also be considered in subjects younger than 40 years who have a family history of gastric cancer and in subjects with long-term medications that might lead to bleeding (antiplatelet agents) or atrophy (proton pump inhibitors). Emerging evidence indicates that H. pylori eradication could be an effective treatment for some extragastric diseases that are unresponsive to conventional therapy. In such conditions, routine screening for eradication of H. pylori has not previously been recommended; a "test-and-treat" approach is suggested in the aforementioned situations. Given that H. pylori eradication is effective when the gastritis is reversible, future indications should be expanded to include acute gastric lesions that show marked improvement upon H. pylori eradication rather than just focusing on chronic gastric lesions. Future indications for H. pylori eradication should focus more on reversible lesions before preneoplastic conditions develop.

GIST: a Gibbs sampler to identify intracellular signal transduction pathways

Identification of intracellular signal transduction pathways plays an important role in understanding the mechanisms of how cells respond to external stimuli. The availability of high throughput microarray expression data and accumulating knowledge of protein-protein interactions have provided us with useful information to infer condition-specific signal transduction pathways. We propose a novel method called Gibbs sampler to Infer Signal Transduction pathways (GIST) to search dys-regulated pathways from large-scale protein-protein interaction networks. GIST incorporates different knowledge sources to extract paths that are highly associated with biological phenotypes or clinical information. One of the most attractive features of GIST is that the algorithm will not only provide the single optimal path according to the defined cost function but also reveal multiple suboptimal paths as alternative solutions, which can be utilized to study the pathway crosstalk. As a proof-of-concept, we test our GIST algorithm on yeast PPI networks and the identified MAPK signaling pathways are well supported by existing biological knowledge. We also apply the GIST algorithm onto a breast cancer patient dataset to show its feasibility of identifying potential pathways for further biological validation.

Gastric cancer epidemiology in Korea

Gastric cancer has been the most commonly diagnosed cancer in Korea although the age-standardized mortality and incidence has decreased gradually during last two decades. Helicobacter pylori infection and cigarette smoking are well-established risk factors, and the role of dietary factors, such as salted foods, fresh vegetables and fruits, soy foods, and processed or grilled meats on gastric carcinogenesis has been suggested. In this review, we review national and international gastric cancer statistics, studies on environmental risk factors conducted in the Korean population, and gastric cancer screening activities.

Ecological study for refrigerator use, salt, vegetable, and fruit intakes, and gastric cancer

We used an ecological approach to determine the correlation between vegetable, fruit and salt intakes, refrigerator use, and gastric cancer mortality in Korean population. Information on fruit and vegetable intakes per capita from the National Health and Nutrition Survey, death certificate data from the National Statistical office, refrigerator per household data from Korean Statistical Information Service, and salt/sodium intake data from a cross-sectional survey were utilized. Correlation coefficients were calculated between vegetable and fruit intakes, refrigerator per household, and gastric cancer mortality and between salt and sodium intakes, and gastric cancer mortality and incidence in the four areas. With 5, 10, and 15 years lag time, refrigerator usage and fruit intake were negatively associated with gastric cancer mortality (p < 0.01), but vegetable intake was not associated with gastric cancer mortality. When estimates of salt/sodium intake evaluated by 24-h urine collection in four areas of Korea were compared to the gastric cancer mortality and incidence in these regions, positive correlation was shown between salt/sodium intake, and gastric cancer incidence and mortality. Negative associations between refrigerator use, fruit intake, and gastric cancer mortality and positive associations between salt/sodium intake and gastric cancer mortality and incidence were suggested.