Global burden of gastric cancer attributable to Helicobacter pylori

We previously estimated that 660,000 cases of cancer in the year 2008 were attributable to the bacterium Helicobacter pylori (H. pylori), corresponding to 5.2% of the 12.7 million total cancer cases that occurred worldwide. In recent years, evidence has accumulated that immunoblot (western blot) is more sensitive for detection of anti‐H. pylori antibodies than ELISA, the detection method used in our previous analysis. The purpose of this short report is to update the attributable fraction (AF) estimate for H. pylori after briefly reviewing new evidence, and to reassess the global burden of cancer attributable to H. pylori. We therefore reviewed the literature for studies comparing the risk of developing non‐cardia gastric cancer (NCGC) in cases and controls, using both ELISA and multiple antigen immunoblot for detection of H. pylori. The results from prospective studies were combined, and the new pooled estimates were applied to the calculation of the AF for H. pylori in NCGC, then to the burden of infection‐related cancers worldwide. Using the immunoblot‐based data, the worldwide AF for H. pylori in NCGC increased from 74.7% to 89.0%. This implies approximately 120,000 additional cases of NCGC attributable to H. pylori infection for a total of around 780,000 cases (6.2% instead of 5.2% of all cancers). These updated estimates reinforce the role of H. pylori as a major cause of cancer.     

Human papillomavirus genotypes in cervical and other HPV-related anogenital cancer in Rwanda,according to HIV status

The study aim was to describe human papillomavirus (HPV)-attributable cancer burden in Rwanda, according to anogenital cancer site, HPV type, age and HIV status. Tissue specimens of cervical, vulvar, vaginal, penile and anal cancer diagnosed in 2012–2018 were retrieved from three cancer referral hospitals and tested for high-risk (HR) HPV DNA. Cervical cancer represented the majority of cases (598 of 738), of which 96.0% were HR-HPV positive. HPV-attributable fractions in other cancer sites varied from 53.1% in 81 penile, through 76.7% in 30 vulvar, 83.3% in 24 vaginal, up to 100% in 5 anal cases. HPV16 was the predominant HR-HPV type in cervical cancer (55.0%), followed by HPV18 (16.6%) and HPV45 (13.4%). HPV16 also predominated in other cancer sites (60–80% of HR-HPV-attributable fraction). For cervical cancer, type-specific prevalence varied significantly by histology (higher alpha-9 type prevalence in 509 squamous cell carcinoma vs. higher alpha-7 type prevalence in 80 adenocarcinoma), but not between 501 HIV-negative and 97 HIV-positive cases. With respect to types targeted, and/or cross-protected, by HPV vaccines, HPV16/18 accounted for 73%, HPV31/33/45/52/58 for an additional 22% and other HR-HPV types for 5%, of HPV-attributable cancer burden, with no significant difference by HIV status nor age. These data highlight the preventive potential of the ongoing national HPV vaccination program in Rwanda, and in sub-Saharan Africa as a whole. Importantly for this region, the impact of HIV on the distribution of causal HPV types was relatively minor, confirming type-specific relevance of HPV vaccines, irrespective of HIV status.     

Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States

Contemporary information on the fraction of cancers that potentially could be prevented is useful for priority setting in cancer prevention and control. Herein, the authors estimate the proportion and number of invasive cancer cases and deaths, overall (excluding nonmelanoma skin cancers) and for 26 cancer types, in adults aged 30 years and older in the United States in 2014, that were attributable to major, potentially modifiable exposures (cigarette smoking; secondhand smoke; excess body weight; alcohol intake; consumption of red and processed meat; low consumption of fruits/vegetables, dietary fiber, and dietary calcium; physical inactivity; ultraviolet radiation; and 6 cancer‐associated infections). The numbers of cancer cases were obtained from the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute; the numbers of deaths were obtained from the CDC; risk factor prevalence estimates were obtained from nationally representative surveys; and associated relative risks of cancer were obtained from published, large‐scale pooled analyses or meta‐analyses. In the United States in 2014, an estimated 42.0% of all incident cancers (659,640 of 1570,975 cancers, excluding nonmelanoma skin cancers) and 45.1% of cancer deaths (265,150 of 587,521 deaths) were attributable to evaluated risk factors. Cigarette smoking accounted for the highest proportion of cancer cases (19.0%; 298,970 cases) and deaths (28.8%; 169,180 deaths), followed by excess body weight (7.8% and 6.5%, respectively) and alcohol intake (5.6% and 4.0%, respectively). Lung cancer had the highest number of cancers (184,970 cases) and deaths (132,960 deaths) attributable to evaluated risk factors, followed by colorectal cancer (76,910 cases and 28,290 deaths). These results, however, may underestimate the overall proportion of cancers attributable to modifiable factors, because the impact of all established risk factors could not be quantified, and many likely modifiable risk factors are not yet firmly established as causal. Nevertheless, these findings underscore the vast potential for reducing cancer morbidity and mortality through broad and equitable implementation of known preventive measures. CA Cancer J Clin 2018;68:31‐54 . © 2017 American Cancer Society .     

Global burden of cutaneous melanoma attributable to ultraviolet radiation in 2012

Ultraviolet radiation (UVR) is a strong and ubiquitous risk factor for cutaneous melanoma, emitted naturally by the sun but also artificial sources. To shed light on the potential impact of interventions seeking to reduce exposure to UVR in both high and low risk populations, we quantified the number of cutaneous melanomas attributable to UVR worldwide. Population attributable fractions and numbers of new melanoma cases in adults due to ambient UVR were calculated by age and sex for 153 countries by comparing the current melanoma burden with historical data, i.e., the melanoma burden observed in a population with minimal exposure to UVR. Secondary analyses were performed using contemporary melanoma incidence rates in dark‐skinned African populations with low UVR susceptibility as reference. Globally, an estimated 168,000 new melanoma cases were attributable to excess UVR in 2012, corresponding to 75.7% of all new melanoma cases and 1.2% of all new cancer cases. This burden was concentrated in very highly developed countries with 149,000 attributable cases and was most pronounced in Oceania, where 96% of all melanomas (representing 9.3% of the total cancer burden) were attributable to excess UVR. There would be approximately 151,000 fewer melanoma cases worldwide were incidence rates in every population equivalent to those observed in selected low‐risk (dark‐skinned, heavily pigmented) reference populations. These findings underline the need for public health action, an increasing awareness of melanoma and its risk factors, and the need to promote changes in behavior that decrease sun exposure at all ages.     

Population attributable proportion and number of cancer cases attributed to potentially modifiable risk factors in Iran in 2020

In the current study, we aimed to calculate the fraction of cancer attributable to modifiable risk factors in Iran in 2020. Population attributable fractions (PAFs) were calculated for established cancer risk factors using three data sources: the national cancer incidence reports, relative risks extracted from global and national meta-analyses, and exposure prevalence from national/subnational population-based surveys. In addition to overall cancers, the PAFs were estimated separately for each cancer site among men and women. Overall, 32.6% of cancers in 2020 in Iran were attributable to known risk factors. The PAF in men (40.2%) was twice as high as in women (21.1%). Cigarette smoking (15.4%), being overweight (5.0%), opium use (3.9%) and H. pylori infection (3.8%) were the leading causes of cancers. For men, the highest PAFs belonged to cigarette smoking (26.3%), opium use (6.8%) and being overweight (3.1%), while for women, the highest PAFs belonged to being overweight (7.2%), H. pylori infection (2.7%) and cigarette smoking (2.7%). Among Iranian men and women, the PAFs of waterpipe smoking were 2% and 0.9%, respectively. A third of incident cancers in Iran are due to modifiable exposures, mainly cigarette smoking, being overweight, and H. pylori infection. Opium consumption and waterpipe smoking collectively accounted for 8.8% of cancer occurrence in men and 1.3% in women in Iran. These emerging risk factors should be taken into consideration in future PAF studies.     

世界范围内9~26岁女性对HPV的认知现状及预防性HPV疫苗的应用现况

持续感染人乳头状瘤病毒(human papilloma virus,HPV)是宫颈癌发生的必要病因.目前HPV疫苗作为宫颈癌的一级预防措施正在全球范围内很多国家和地区实施.世界卫生组织(WHO)推荐9岁以上女性接种HPV疫苗,而9～26岁被认为是最佳接种年龄,很多国家也对接种年龄界定在9～26岁之间.2016年7月18日,HPV二价疫苗(HPV 16和18型)希瑞适(R)(Cervarix(R))获得中国食品药品监督管理局(CFDA)的上市许可,它适用于9～25岁女性,采用3剂免疫接种程序.而该人群对于HPV的认知以及疫苗接种的组织形式是影响HPV疫苗计划成功实施的重要因素.全文综述了国内外9～26岁女性关于HPV认知的现状及HPV疫苗应用现况,为将来在我国适龄人群中成功推广和接种预防性HPV疫苗提供参考依据.     

预防性 HPV 疫苗的临床应用进展及思考

宫颈癌是女性生殖系统最常见的恶性肿瘤,并且高危型人乳头瘤病毒（human papillomavirus, HPV）持续感染与宫颈癌的密切关系已经得到流行病学及临床研究证实。因此,HPV 疫苗在预防 HPV 持续感染及宫颈相关病变等方面备受瞩目。本文对目前美国 FDA 批准上市的3种预防性疫苗的临床应用进展进行综述,同时列举出一些尚存在争议的问题,旨在引起人们的重视及共同思考。     

Population attributable risks for breast cancer in Swedish women by morphological type

The purpose of this population-based cohort study is to describe the etiology of invasive and in situ breast cancer, using the Swedish Family-Cancer Database. A total of 1,028,455 women, aged 40–61 years, were followed from 1993 through 2004. Invasive and in situ breast cancer was identified in 27,243 and 3,496 women, respectively, with data on family history, reproductive variables, residential region and socioeconomic status. Relative risks (RRs) and population attributable fractions (PAFs) were estimated by Poisson regression. The overall PAF of invasive breast cancer was 5.3% for family history and 17.9% for reproductive factors. Morphology-specific PAFs were calculated for ductal (family history: 5.2%, reproductive factors: 16.6%), lobular (family history: 6.2%, reproductive factors: 19.9%) and comedo types (family history: 5.2%, reproductive factors: 25.9%). The corresponding PAFs of in situ tumors were higher due to family history and reproductive factors. Family history, late age at first birth and high socioeconomic status were associated with elevated risks in all morphologies, whereas low parity did not have an impact on the invasive and in situ lobular and comedo tumors. The risks for women with a family history were the highest, but these women accounted for the smallest proportion of the cases, thus resulting in the lowest PAFs.     

Fraction and incidence of liver cancer attributable to hepatitis B and C viruses worldwide

High‐quality data on liver cancers by probable cause are scarce in many regions of the world. The United Nations recently set a goal of eliminating viral hepatitis as a major public health threat by 2030. We aimed to estimate the number of new cases of cancers attributable to hepatitis B virus (HBV) and hepatitis C virus (HCV) at a global, regional and country level, and by development status. We used data on the prevalence of HBV and HCV in hepatocellular carcinoma from a systematic review including 119,000 cases in 260 studies covering 50 countries. A statistical model was constructed to extrapolate empirical data to countries without prevalence data. Country‐specific numbers of liver cancer cases attributable to HBV and HCV were calculated using data from GLOBOCAN 2012. Globally, 770,000 cases of liver cancer occurred worldwide in 2012, of which 56% (95% CI: 52–60) were attributable to HBV and 20% (95% CI: 18–22) to HCV. Currently, HBV causes approximately two out of three cases of liver cancer in less developed countries but one in four cases in more developed countries and shows a much higher degree of geographical aggregation in Eastern Asia and sub‐Saharan Africa than HCV. These estimates help set priorities for liver cancer prevention. High‐coverage HBV vaccination will be transformational in HBV‐endemic countries but the prevention of HCV transmission and the treatment of chronic carriers of both viruses requires new scalable solutions.     

Proportion and number of cancer cases and deaths attributable to behavioral risk factors in Vietnam

Identifying modifiable risk factors that contribute to cancer is essential in setting up preventive strategies. Therefore, this study aimed to estimate the number and proportion of cancer cases and deaths attributable to five behavior-related risk factors—tobacco smoking, second-hand smoking, alcohol consumption, high body mass index and insufficient physical activity in Vietnam in 2020. Population attributable fractions were calculated for relationships of risk factors and cancer types based on sufficient evidence according to IARC or strong evidence according to WCRF/AICR. Relative risks were retrieved from meta-analyses where possible. Prevalence of risk factors was obtained from the most current available nationally representative population surveys in Vietnam. Cancer cases and deaths were obtained from GLOBOCAN 2020. An estimated 40.5% of all cancer cases in men (39 924 cases) and 7.8% in women (6542 cases) were attributable to these risk factors. The proportions of cancer deaths attributable to these risk factors were 44.0% in men (32 807 cases) and 8.9% in women (4235 cases). Tobacco smoking was the leading cause of cancer cases and deaths in men, followed by alcohol consumption and high BMI. In women, high BMI accounted for the highest proportion of cancer cases and second-hand smoking accounted for the highest proportion of cancer deaths. Lung and upper aerodigestive tract cancer cases and deaths could have been reduced at least by half if these risk factors had been eliminated. To reduce cancer incidence and mortality, preventive actions focusing on tobacco control are likely to have the most significant impact, especially in men.     

Burden of disease from breast cancer attributable to smoking and second-hand smoke exposure in Europe

Smoking and second-hand smoke (SHS) exposure have been recently linked to a higher risk of breast cancer in women. The aim of this work is to estimate the number of deaths and disability-adjusted life years (DALYs) from breast cancer attributable to these two risk factors in the European Union (EU-28) in 2017. The comparative risk assessment method was used. Data on prevalence of smoking and SHS exposure were extracted from the Eurobarometer surveys, relative risks from a recent meta-analysis, and data on mortality and DALYs from breast cancer were estimated from the Global Burden of Disease, Injuries and Risk Factors Study. In 2017, 82 239 DALYs and 3354 deaths from breast cancer in the EU-28 could have been avoided by removing exposure to these two risk factors (smoking and SHS exposure). The proportion of DALYs from breast cancer lost respectively from smoking and SHS exposure was 2.6% and 1.0%, although geographically distributed with significant heterogeneity. These results represent the first estimates of breast cancer burden in women attributable to smoking and SHS exposure for the EU-28. It is important to increase awareness among women, health professionals and wider society of the association between smoking, SHS exposure and breast cancer, a relationship that is not widely recognised or discussed.     

Introduction and sustained high coverage of the HPV bivalent vaccine leads to a reduction in prevalence of HPV 16/18 and closely related HPV types

Background:

In 2008, a national human papillomavirus (HPV) immunisation programme began in Scotland for 12–13 year old females with a three-year catch-up campaign for those under the age of 18. Since 2008, three-dose uptake of bivalent vaccine in the routine cohort aged 12–13 has exceeded 90% annually, while in the catch-up cohort overall uptake is 66%.

Methods:

To monitor the impact of HPV immunisation, a programme of national surveillance was established (pre and post introduction) which included yearly sampling and HPV genotyping of women attending for cervical screening at age 20. By linking individual vaccination, screening and HPV testing records, we aim to determine the impact of the immunisation programme on circulating type-specific HPV infection particularly for four outcomes: (i) the vaccine types HPV 16 or 18 (ii) types considered to be associated with cross-protection: HPV 31, 33 or 45; (iii) all other high-risk types and (iv) any HPV.

Results:

From a total of 4679 samples tested, we demonstrate that three doses (n=1100) of bivalent vaccine are associated with a significant reduction in prevalence of HPV 16 and 18 from 29.8% (95% confidence interval 28.3, 31.3%) to 13.6% (95% confidence interval 11.7, 15.8%). The data also suggest cross-protection against HPV 31, 33 and 45. HPV 51 and 56 emerged as the most prevalent (10.5% and 9.6%, respectively) non-vaccine high-risk types in those vaccinated, but at lower rates than HPV 16 (25.9%) in those unvaccinated.

Conclusions:

This data demonstrate the positive impact of bivalent vaccination on the prevalence of HPV 16, 18, 31, 33 and 45 in the target population and is encouraging for countries which have achieved high-vaccine uptake.     

HPV Vaccination: An Underused Strategy for the Prevention of Cancer

Human papillomavirus (HPV) vaccination prevents cervical, head and neck, and anogenital cancers. However, global HPV vaccine coverage falls short of global targets and has seen unexpected and dramatic declines in some countries. This paper synthesizes the impact of HPV on the global burden of cancer and the potential benefit of HPV vaccination. Approximately 5% of the world’s cancers are specifically attributed to HPV. While the greatest global burden of HPV is cervical cancers in low- and middle-income countries, HPV-associated head and neck cancers are increasing in high-income countries and have surpassed cervical cancer as the primary HPV-associated cancer in some countries. Therefore, it is also critical to improve gender-neutral HPV vaccination. Understanding the modifiable drivers of vaccine acceptance and uptake is important for increasing HPV vaccination. The Behavioural and Social Drivers of Vaccination framework is broadly applied to identify key factors associated with HPV vaccination including domains concerning practical issues, motivation, social processes, and thinking and feeling. Among the behavioural strategies available to reduce the incidence and mortality of cancer, increasing HPV vaccination stands out as having unrealized potential to prevent disease, financial cost, and psychological distress. An understanding of the shifting burden of HPV and the factors associated with vaccination can be leveraged to regularly measure these factors, develop interventions to promote vaccine uptake, and improve global HPV vaccine coverage. Future research in diverse contexts is necessary to investigate the barriers and facilitators of global HPV vaccination.     

Extended duration of the detectable stage by adding HPV test in cervical cancer screening

The human papillomavirus test (HPV) test could improve the (cost-) effectiveness of cervical screening by selecting women with a very low risk for cervical cancer during a long period. An analysis of a longitudinal study suggests that women with a negative Pap smear and a negative HPV test have a strongly reduced risk of developing cervical abnormalities in the years following the test, and that HPV testing lengthens the detectable stage by 2-5 years, compared to Pap smear detection alone.     

Knowledge of Human Papillomavirus (HPV) Infection,Cervical Cancer,and HPV Vaccine and its Correlates among Medical Students in Southwest China: a Multi-center Cross-sectional Survey

Background: Since cervical cancer can be prevented and controlled through human papillomavirus (HPV)vaccination, it is important to train health care providers and provide them with appropriate knowledge.This study aimed to understand the level of HPV related knowledge among medical students and correlatesin Southwest China in order to address any potential gap in their knowledge base. Methods: We conducted across-sectional survey among medical students in six selected universities across Southwest China based on apretested questionnaire regarding HPV infection, cervical cancer, and HPV vaccines. Results: We successfullysurveyed 1, 878 medical students, of whom 32.1% were males and 67.9% were females. Their mean age was 20.8(standard deviation: 1.3) years. 91.8% of them were ethnic Han Chinese, and 43.8% were students in clinicalmedicine. While 76.5% had heard of HPV only 48.8% knew that the prevention of cervical cancer was possiblethrough HPV vaccination. Only 42.9% of the male and 49.2% of the female students correctly answered over 10out of 22 questions on HPV related knowledge. Female students appeared to know more about HPV and HPVvaccination (OR: 1.39; 95% CI: 1.11-1.75). In addition, the student knowledge improved with the grade (p<0.001).University courses were the most selected source of knowledge about HPV vaccination (66.4%). 83.6% of malesand 91.4% of females were willing to have more HPV related education by experts (p<0.001). Only 10.1% of thestudents acknowledged that people had asked for their advice regarding HPV vaccination. Conclusions: Oursurvey indicates that medical students from Southwest China have poor knowledge of HPV and HPV vaccination,but are willing to receive more relevant information. Targeted education should be incorporated into schoolcourses to inform these future health care providers and ensure success of programs for cervical cancer controland prevention.     

Cutaneous melanoma attributable to solar radiation in Cali,Colombia

Estimating the population attributable fraction (PAF) of melanomas due to sun exposure is challenging as there are no unexposed population nor reliable exposure data. In high incidence countries, a historic cohort of the South Thames cancer registry was used as a minimally exposed population using the formula PAF = (observed incidence‐incidence in minimally exposure)/observed incidence. In this study, we apply this method, constructing a minimally exposed cohort for Colombia and also using the historical South Thames data, using melanoma incidence data from the population‐based cancer registry of Cali, Colombia for the period 1967–2012. The historic cohort incidence rates were very similar to those of Thames, but cohort effects were smaller for women and nonexistent for men. Age‐specific incidence rates of these minimally exposed cohorts were applied to recent population numbers. For females, PAFs were 19% using the historic Thames cohort and 25% using the historic Cali cohort, corresponding numbers for males were 62% (vs. Thames) and 0% (vs. Cali). Taking into account the incidence rates of acral melanomas, which are not sun related, the PAF increased in women to 26% (vs. Thames) and 34% (vs. Cali) and for men 77% (vs. Thames). This exercise shows the modest contribution of exposure to ultraviolet radiation in the burden of melanoma in low‐incidence countries, as well as the importance to take into consideration the acral lentiginous melanomas.