A modeling analysis to compare eligibility strategies for lung cancer screening in Brazil

BACKGROUND

Country-specific evidence is needed to guide decisions regarding whether and how to implement lung cancer screening in different settings. For this study, we estimated the potential numbers of individuals screened and lung cancer deaths prevented in Brazil after applying different strategies to define screening eligibility.

METHODS

We applied the Lung Cancer Death Risk Assessment Tool (LCDRAT) to survey data on current and former smokers (ever-smokers) in 15 Brazilian state capital cities that comprise 18% of the Brazilian population. We evaluated three strategies to define eligibility for screening: (1) pack-years and cessation time (≥30 pack-years and <15 years since cessation); (2) the LCDRAT risk model with a fixed risk threshold; and (3) LCDRAT with age-specific risk thresholds.

FINDINGS

Among 2.3 million Brazilian ever-smokers aged 55-79 years, 21,459 (95%CI 20,532-22,387) lung cancer deaths were predicted over 5 years without screening. Applying the fixed risk-based eligibility definition would prevent more lung cancer deaths than the pack-years definition [2,939 (95%CI 2751-3127) vs. 2,500 (95%CI 2318-2681) lung cancer deaths], and with higher screening efficiency [NNS=177 (95%CI 170-183) vs. 205 (95%CI 194-216)], but would tend to screen older individuals [mean age 67.8 (95%CI 67.5-68.2) vs. 63.4 (95%CI 63.0-63.9) years]. Applying age-specific risk thresholds would allow younger ever-smokers to be screened, although these individuals would be at lower risk. The age-specific thresholds strategy would avert three-fifths (60.1%) of preventable lung cancer deaths [N = 2629 (95%CI 2448-2810)] by screening 21.9% of ever-smokers.

INTERPRETATION

The definition of eligibility impacts the efficiency of lung cancer screening and the mean age of the eligible population. As implementation of lung screening proceeds in different countries, our analytical framework can be used to guide similar analyses in other contexts. Due to limitations of our models, more research would be needed.

Temporal and geographical variations of thyroid cancer incidence and mortality in France during 1986-2015: The impact of overdiagnosis

BACKGROUND

France is among the countries showing fastest growth of thyroid cancer (TC) incidence and highest incidence rates in Europe. This study aimed to clarify the temporal and geographical variations of TC in France and to quantify the impact of overdiagnosis.

METHODS

We obtained TC incidence data in 1986-2015, and mortality data in 1976-2015, for eight French departments covering 8% of the national population, and calculated the age-standardised rates (ASR). We estimated the average annual percent changes (AAPC) of TC incidence, overall and by department and histological subtype. Numbers and proportions of TC cases attributable to overdiagnosis were estimated by department and period, based on the comparison between the shape of the age-specific curves with that observed prior to changes in diagnostic practice.

RESULTS

During 1986-2015, there were 13,557 TC cases aged 15-84 years. Large variations of TC incidence were observed across departments, with the highest ASR and the fastest increase in Isère. Papillary subtype accounted for 82.8% of the cases, and presented an AAPC of 7.0% and 7.6% in women and men, respectively. Anaplastic TC incidence decreased annually 3.0% in women and 0.8% in men. Mortality rates declined consistently for all departments. The absolute number (and proportion) of TC cases attributable to overdiagnosis grew from 1074 (66%) in 1986-1995 to 3830 (72%) in 2006-2015 in women, and varied substantially across departments.

CONCLUSIONS

Overdiagnosis plays an important role in the temporal and regional variations of TC incidence in France. Monitoring the time trends and regulating the regional healthcare practice are needed to reduce its impact.

Incidence of Clinically Relevant Thyroid Cancers Remains Stable for Almost a Century: A Population-Based Study

OBJECTIVE

To examine the trends in incidence of clinically relevant thyroid cancers within the overall rising incidence of thyroid cancers.

PATIENTS AND METHODS

This is a population-based cohort study conducted using the Rochester Epidemiology Project database to identify all new cases of thyroid cancer in Olmsted County, Minnesota, between January 1, 1935, and December 31, 2018. We extracted information about demographics and tumor pathologic type, size, and invasiveness. Clinically relevant cancers included aggressive histology or presence of metastatic disease, size larger than 4 cm, and gross extrathyroidal tumor invasion.

RESULTS

Between 1935 and 2018, 596 thyroid cancer cases were diagnosed (mean age, 46.4 years; 72% female; 87% papillary cancers; and median tumor size, 1.5 cm). The sex- and age-adjusted incidence of thyroid cancer increased from 1.3 per 100,000 person-years (p-y) from 1935-1949 to 12.0 per 100,000 p-y in 2010-2018, corresponding to an absolute change per decade of 1.4 (95% CI, 0.7 to 2.2). There was a nonsignificant period absolute change for patients with tumor greater than 4 cm (0.03; 95% CI, -0.2 to 0.3), with evidence of tumor invasion (0.1; 95% CI, -0.1 to 0.4), and with aggressive histology or presence of metastatic disease (0.2; 95% CI, -0.1 to 0.6). Thyroid cancer mortality was unchanged over the observation period.

CONCLUSION

Incidence rates of clinically relevant thyroid cancers, as defined by histology, size, and invasiveness, have not changed significantly in 80 years. The rising thyroid cancer incidence is driven by indolent thyroid cancers.

Risk of thyroid as a first or second primary cancer. A population-based study in Italy, 1998-2012

BACKGROUND

The number of patients living after a cancer diagnosis is increasing, especially after thyroid cancer (TC). This study aims at evaluating both the risk of a second primary cancer (SPC) in TC patients and the risk of TC as a SPC.

METHODS

We analyzed two population-based cohorts of individuals with TC or other neoplasms diagnosed between 1998 and 2012, in 28 Italian areas covered by population-based cancer registries. Standardized incidence ratios (SIRs) of SPC were stratified by sex, age, and time since first cancer.

RESULTS

A total of 38,535 TC patients and 1,329,624 patients with other primary cancers were included. The overall SIR was 1.16 (95% CI: 1.12-1.21) for SPC in TC patients, though no increase was shown for people with follicular (1.06) and medullary (0.95) TC. SPC with significantly increased SIRs was bone/soft tissue (2.0), breast (1.2), prostate (1.4), kidney (2.2), and hemolymphopoietic (1.4) cancers. The overall SIR for TC as a SPC was 1.49 (95% CI: 1.42-1.55), similar for all TC subtypes, and it was significantly increased for people diagnosed with head and neck (2.1), colon-rectum (1.4), lung (1.8), melanoma (2.0), bone/soft tissue (2.8), breast (1.3), corpus uteri (1.4), prostate (1.5), kidney (3.2), central nervous system (2.3), and hemolymphopoietic (1.8) cancers.

CONCLUSIONS

The increased risk of TC after many other neoplasms and of few SPC after TC questions the best way to follow-up cancer patients, avoiding overdiagnosis and overtreatment for TC and, possibly, for other malignancies.

Trends in thyroid function testing, neck ultrasound, thyroid fine needle aspiration, and thyroidectomies in North-eastern Italy

PURPOSE

Evidence of an increased diagnostic pressure on thyroid has emerged over the past decades. This study aimed to provide estimates of a wide spectrum of surveillance indicators for thyroid dysfunctions and diseases in Italy.

METHODS

A population-based study was conducted in North-eastern Italy, including 11.7 million residents (20% of the total Italian population). Prescriptions for TSH testing, neck ultrasound or thyroid fine needle aspiration (FNA), surgical procedures, and drugs for hypo- or hyperthyroidism were extracted from regional health databases. Proportions and rates of selected examinations were calculated from 2010 to 2017, overall and by sex, calendar years, age, and region.

RESULTS

Between 2010 and 2017 in North-eastern Italy, 24.5% of women and 9.8% of men received at least one TSH test yearly. In 2017, 7.1% of women and 1.5% of men were prescribed drugs for thyroid dysfunction, 94.6% of whom for hypothyroidism. Neck ultrasound examinations were performed yearly in 6.9% of women and 4.6% of men, with a nearly two-fold variation between areas. Thyroid FNA and thyroidectomies were three-fold more frequent in women (394 and 85 per 100,000) than in men (128 and 29 per 100,000) with a marked variation between areas. Both procedures decreased consistently after 2013.

CONCLUSIONS

The results of this population-based study describe recent variations over time and between surrounding areas of indicators of 'diagnostic pressure' on thyroid in North-eastern Italy. These results emphasize the need to harmonize practices and to reduce some procedures (e.g., neck ultrasound and total thyroidectomies) in certain areas.

Thyroid cancer incidence trends by histology in 25 countries: a population-based study

BACKGROUND

The incidence of thyroid cancer has increased in different populations worldwide in the past 30 years. We present here an overview of international trends of thyroid cancer incidence by major histological subtypes.

METHODS

We did a population-based study with data for thyroid cancer incidence collected by the International Agency for Research on Cancer (IARC) for the period 1998-2012. Data were extracted from the Cancer Incidence in Five Continents plus compendium. We selected data for 25 countries that had a population of more than 2 million individuals covered by cancer registration (87 registries in total). Further criteria were that the selected registration areas had to have a proportion of unspecified thyroid cancer of less than 10% and analyses were restricted to individuals aged 20-84 years. We calculated age-specific incidence rates and age-standardised rates per 100 000 person-years for individuals aged 20 to 84 years, and assessed trends by country, sex, and major histological subtype (papillary, follicular, medullary, or anaplastic) based on absolute changes in age-standardised incidence rates between 1998-2002 and 2008-12.

FINDINGS

Papillary thyroid cancer was the main contributor to overall thyroid cancer in all the studied countries, and was the only histological subtype that increased systematically in all countries, although with large variability between countries. In women, the age-standardised incidence rate of papillary thyroid cancer during 2008-12 ranged from 4·3-5·3 cases per 100 000 person-years in the Netherlands, the UK, and Denmark, to 143·3 cases per 100 000 women in South Korea. For men during the same period, the age-standardised incidence rates of papillary thyroid cancer per 100 000 person-years ranged from 1·2 cases per 100 000 in Thailand to 30·7 cases per 100 000 in South Korea. In many countries in Asia, the increase in papillary thyroid cancer rates in women was particularly pronounced after the year 2000; rates stabilised since around 2009 in the USA, Austria, Croatia, Germany, Slovenia, Spain, Lithuania, and Bulgaria. Temporal trends for follicular and medullary thyroid cancer did not show consistent patterns across countries, but slight decreases were seen for anaplastic thyroid cancer in 21 of 25 countries between 1998-2002, and 2008-12. In 2008-12, age-standardised rates for the follicular subtype ranged between 0·5 and 2·5 cases per 100 000 women (and between 0·3 and 1·5 per 100 000 men), while those for the medullary subtype were always less than 1 case per 100 000 women or men, and for anaplastic thyroid cancer less than 0·2 cases per 100 000 women or men.

INTERPRETATION

In the period from 1998 to 2012, the rapid increases in thyroid cancer incidence were observed only for papillary thyroid cancer, the subtype more likely to be found in a subclinical form and therefore detected by intense scrutiny of the thyroid gland.

FUNDING

French Institut National du Cancer, Italian Association for Cancer Research, Italian Ministry of Health.

Global patterns and trends in incidence and mortality of thyroid cancer in children and adolescents: a population-based study

BACKGROUND

There has been a considerable increase in thyroid cancer incidence among adults in several countries in the past three decades, attributed primarily to overdiagnosis. We aimed to assess global patterns and trends in incidence and mortality of thyroid cancer in children and adolescents, in view of the increased incidence among adults.

METHODS

We did a population-based study of the observed incidence (in 49 countries and territories) and mortality (in 27 countries) of thyroid cancer in children and adolescents aged 0-19 years using data from the International Incidence of Childhood Cancer Volume 3 study database, the WHO mortality database, and the cancer incidence in five continents database (CI5plus; for adult data [age 20-74 years]). We analysed temporal trends in incidence rates, including absolute changes in rates, and the strength of the correlation between incidence rates in children and adolescents and in adults. We calculated the average annual number of thyroid cancer deaths and the age-standardised mortality rates for children and adolescents.

FINDINGS

Age-standardised incidence rates of thyroid cancer among children and adolescents aged 0-19 years ranged from 0·4 (in Uganda and Kenya) to 13·4 (in Belarus) cancers per 1 million person-years in 2008-12. The variability in the incidence rates was mostly accounted for by the papillary tumour subtype. Incidence rates were almost always higher in girls than in boys and increased with age in both sexes. Rapid increases in incidence between 1998-2002 and 2008-12 were observed in almost all countries. Country-specific incidence rates in children and adolescents were strongly correlated (r>0·8) with rates in adults, as were the temporal changes in the respective incidence rates (r>0·6). Thyroid cancer deaths in those aged younger than 20 years were less than 0·1 per 10 million person-years in each country.

INTERPRETATION

The pattern of thyroid cancer incidence in children and adolescents mirrors the pattern seen in adults, suggesting a major role for overdiagnosis, which, in turn, can lead to overtreatment, lifelong medical care, and side effects that can negatively affect quality of life. We suggest that the existing recommendation against screening for thyroid cancer in the asymptomatic adult population who are free from specific risk factors should be extended to explicitly recommend against screening for thyroid cancer in similar populations of children and adolescents.

FUNDING

International Agency for Research on Cancer and the Union for International Cancer Control; French Institut National du Cancer; Italian Association of Cancer Research; and Italian Ministry of Health.

Profiling global cancer incidence and mortality by socioeconomic development

Economic and living conditions have improved over time in most countries, although often in association with detrimental lifestyle and environmental changes that are major determinants of cancer. In this ecological study, we assess the association between national socioeconomic levels and incidence and mortality rates for all cancers combined and 27 cancer types, in 175 countries. We obtained national level cancer incidence and mortality estimates for 2018 from GLOBOCAN and computed an index of socioeconomic development based on national education and income levels extracted from the United Nations Development Programme. Cancer incidence rates are strongly positively associated with the national socioeconomic level for all cancers combined and for a large number of cancer types, in both sexes. Conversely, the association between socioeconomic development and cancer mortality rates is less clear. The most common pattern for type-specific cancers is an increasing incidence rate with a relatively stable mortality rate as socioeconomic development increases. Despite the high incidence rates for many cancer types, mortality rates are relatively low in high-income countries, partly due to the availability of early detection and effective treatments. As socioeconomic development continues to rise, countries with currently low- and medium-development levels may experience large increases in the incidence of several cancers. Given the limited resources and lack of infrastructure, increases in incidence rates in low-income countries will likely be paralleled by increases in mortality rates. Efforts to plan, implement and evaluate prevention programs must therefore be considered as greater priorities in Low- and Middle-income countries.

Time trends and other sources of variation in Helicobacter pylori infection in mainland China: A systematic review and meta-analysis

BACKGROUND

Helicobacter pylori (H pylori) is a carcinogen that causes a huge burden of gastric cancer in China. We aimed to evaluate the temporal trends and other sources of variation of H pylori infection in adults from mainland China.

MATERIALS AND METHODS

For this systematic review and meta-analysis, we searched PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases for articles published from January 1983 to June 2020. We included studies reporting H pylori prevalence in adults and then applied random effect meta-analyses to obtain pooled prevalence estimates for all studies and subgroups. Sources of heterogeneity were investigated by moderator analysis, and time trends were assessed through random effect meta-regression.

RESULTS

Of the 2121 studies identified, 98 were eligible for inclusion. The pooled estimate of 670 572 participants from 26 provinces during 1983-2018 was 49.6% (95% CI: 46.9%, 52.4%). H pylori prevalence varied considerably, ranging from 20.6% to 81.8%. Periods, urban/rural status, detection method, and study design explained 18.8%, 24.0%, 17.8%, and 30.4% of the heterogeneity, respectively. Overall, H pylori prevalence declined by -0.9% (95% CI: -1.1%, -0.6%) annually. Consistent declines in prevalence were observed by sex, age, and study characteristics.

CONCLUSIONS

Helicobacter pylori prevalence is slowly decreasing over time in mainland China, but the low declining speed is not enough to have a major impact on gastric cancer incidence for many years. The time trends and the large heterogeneity should be taken into account when conducting regional comparisons, disease burden estimations, and customized strategy making.

Thyroid Cancer Incidence in India Between 2006 and 2014 and Impact of Overdiagnosis

CONTEXT/OBJECTIVE

Increases of thyroid cancer (TC) incidence emerged in the past several decades in several countries. This study aimed to estimate time trends of TC incidence in India and the proportion of TC cases potentially attributable to overdiagnosis by sex, age, and area.

DESIGN

TC cases aged 0 to 74 years reported to Indian cancer registries during 2006 through 2014 were included. Age-standardized incidence rates (ASR) and TC overdiagnosis were estimated by sex, period, age, and area.

RESULTS

Between 2006 to 2008 and 2012 to 2014, the ASRs for TC in India increased from 2.5 to 3.5/100,000 women (+37%) and from 1.0 to 1.3/100,000 men (+27%). However, up to a 10-fold difference was found among regions in both sexes. Highest ASRs emerged in Thiruvananthapuram (14.6/100,000 women and 4.1/100,000 men in 2012-2014), with 93% increase in women and 64% in men compared with 2006 to 2008. No evidence of overdiagnosis was found in Indian men. Conversely, overdiagnosis accounted for 51% of TC in Indian women: 74% in those aged < 35 years, 50% at ages 35 to 54 years, and 30% at ages 55 to 64 years. In particular, 80% of TC overdiagnosis in women emerged in Thiruvananthapuram, whereas none or limited evidence of overdiagnosis emerged in Kamrup, Dibrugarh, Bhopal, or Sikkim.

CONCLUSIONS

Relatively high and increasing TC ASRs emerged in Indian regions where better access to health care was reported. In India, as elsewhere, new strategies are needed to discourage opportunistic screening practice, particularly in young women, and to avoid unnecessary and expensive treatments. Present results may serve as a warning also for other transitioning countries.

Long-Term Declines of Thyroid Cancer Mortality: An International Age-Period-Cohort Analysis

Background: Thyroid cancer (TC) incidence rates have been increasing in many countries, predominantly due to overdiagnosis. It is, however, not yet clear whether a true increase in exposure to risk factors might have also contributed to the TC epidemic. We assessed the TC mortality trends, which should not be affected by overdiagnosis, to disentangle the specific contribution of period and cohort effects. Methods: We analyzed long-term mortality data in 24 countries from 5 continents using age-period-cohort (APC) models. Nonidentifiability of the APC models was circumvented by integrating evidence of a consistent relationship between age and TC mortality, allowing to estimate period and cohort linear effects. Results: Substantial heterogeneity existed in the historical TC mortality rates across countries, but long-term rates declined over time in most of the countries, converging around a value of 0.5/100,000. The shape of the age-specific curves was consistently similar across countries and periods, resembling straight lines on the log-log scale, with the slopes ranging between 4.0 and 6.0. Both period and cohort effects showed long-term declines in most countries for both genders. In some countries, such as the United States, Canada, and Australia, substantial long-term declines by period were visible until the 1980s and 1990s, but then stabilized or increased slightly. Declining cohort effects were also seen in almost all countries, and were particularly pronounced in women from Switzerland, whereas stable cohort effects were recorded in South Africa. Although there were some indications of possible increasing risks of deaths among the youngest generations in some countries for both men and women, changes are too recent to be treated as unequivocal and estimates suffered from large statistical variability due to small numbers of deaths. Conclusions: Global long-term declines in TC mortality have been accompanied by downward trends in both period and cohort effects. Our results suggest lack of evidence of a possible major contribution of "real" risk factors in TC mortality, and indirectly confirm the main role of overdiagnosis in the epidemic of TC incidence.

Thyroid cancer incidence in India between 2006 and 2014 and impact of overdiagnosis

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Background: Increases of thyroid cancer (TC) incidence emerged in the last decades in several countries. This study aimed to estimate time trends of TC incidence in India and the proportion of TC cases potentially attributable to overdiagnosis by sex, age, and area. Methods: TC cases aged 0-74 years reported to Indian cancer registries during 2006- 2014 were included. Age-standardized incidence rates (ASR) and TC overdiagnosis were estimated by sex, period, age, and area. Results: Between 2006-2008 and 2012-2014, the ASRs for TC in India increased from 2.5 to 3.5/100,000 women (+37%) and from 1.0 to 1.3/100.000 men (+27%). However, up to a 10-fold difference was found among regions in both sexes. Highest ASRs emerged in Thiruvananthapuram (14.6/100,000 women and 4.1/100,000 men in 2012- 2014), with 93% increase in women and 64% in men compared to 2006-2008. No evidence of overdiagnosis was found in Indian men. Conversely, overdiagnosis accounted for 51% of TC in Indian women: 74% in those aged < 35 years, 50% at ages 35-54 years, and 30% at ages 55-64 years. In particular, 80% of TC overdiagnosis in women emerged in Thiruvananthapuram, while none or limited evidence of overdiagnosis emerged in Kamrup, Dibrugarh, Bhopal, and Sikkim. Conclusions: Relatively high and increasing TC ASRs emerged in Indian regions where better access to healthcare was reported. In India, as elsewhere, new strategies are needed to discourage opportunistic screening practice, particularly in young women, and to avoid unnecessary and expensive treatments. Present results may serve as a warning also for other transitioning countries.

Are U.S. trends a barometer of future cancer transitions in emerging economies?

The currently high cancer incidence rates in the U.S. and other high-income countries have been strongly affected by the acquisition of environmental and lifestyle risk factors that accompanied socioeconomic growth in the second half of the last century. The very same factors are now operating in many low- and middle-income countries (LMIC) undergoing rapid socioeconomic transition. A parallel is drawn between the past cancer trends in the U.S. and those anticipated in LMIC transitioning towards higher levels of socioeconomic development. We expect to see a major upsurge in the (still low to intermediate) cancer incidence and mortality rates in LMIC over the next decades, which coupled with population aging and growth, would translate to a scale of individuals diagnosed with, living and dying from cancer unparalleled in history. On account of resource constraints and organizational limitations, prevention strategies need to be prioritized in LMIC.

Thyroid cancer in Friuli Venezia Giulia, northeastern Italy: incidence, overdiagnosis, and impact of type of surgery on survival

BACKGROUND

Incidence rates of thyroid cancer (TC) increased in the last decades worldwide. This study aimed to describe TC incidence in the Friuli Venezia Giulia (FVG) region, to estimate the quota of overdiagnosis, and to investigate the impact of surgery on long-term survival after TC diagnosis.

METHODS

TC cases reported to the FVG population-based cancer registry during 2002-2013, aged <85 years, were included. Age standardized rates (ASR) on the European population were computed, while proportion of TC overdiagnosis was estimated in comparison with expected age-specific incidence rates from published time series. Adjusted hazard ratios of death, with 95% confidence intervals, were also estimated.

RESULTS

During 2002-2013, 1701 TC cases were reported to the FVG cancer registry, with papillary TC (78.2%) as the most frequent histologic type. ASR increased from 12.4 to 16.5 in women and from 4.3 to 6.2 in men (+33.1% and +44.2%, respectively). Overdiagnosis was estimated as 79% of TC cases in women and 64% in men. Almost all TC cases (97.1%) underwent surgery, including 84.6% of women and 78.9% of men who underwent total thyroidectomy. Up to 10 years after TC diagnosis, the type of surgery did not appear to influence survival.

CONCLUSIONS

This study documented an increase in TC incidence in FVG in the last decade, with overdiagnosis accounting for a large proportion of TC diagnoses and total thyroidectomy in more than 80% of cases. These findings suggest reconsidering thyroid screening practice and aggressive therapeutic strategies, as recommended by new TC guidelines.

Thyroid cancer "epidemic" also occurs in low- and middle-income countries

Thyroid cancer incidence varies greatly between and within high-income countries (HICs), and overdiagnosis likely plays a major role in these differences. Yet, little is known about the situation in low- and middle-income countries (LMICs). We compare up-to-date thyroid cancer incidence and mortality at national and subnational levels. 599,851 thyroid cancer cases in subjects aged 20-74 reported in Cancer Incidence in Five Continents volume XI from 55 countries with at least 0.5 million population, aged 20-74 years, covered by population-based cancer registration, and 22,179 deaths from the WHO Mortality Database for 36 of the selected countries, over 2008-2012, were included. Age-standardized rates were computed. National incidence rates varied 50-fold. Rates were 4 times higher among women than men, with similar patterns between countries. The highest rates (>25 cases per 100,000 women) were observed in the Republic of Korea, Israel, Canada, the United States, Italy, France, and LMICs such as Turkey, Costa Rica, Brazil, and Ecuador. Incidence rates were low (<8) in a few HICs (the Netherlands, the United Kingdom, and Denmark) and lowest (3-4) in some LMICs (such as Uganda and India). Within-country incidence rates varied up to 45-fold, with the largest differences recorded between rural and urban areas in Canada (HIC) and Brazil, India, and China (LMICs). National mortality rates were very low (<2) in all countries and in both sexes, and highest in LMICs. The very high thyroid cancer incidence and low mortality rates in some LMICs also strongly suggest a major role of overdiagnosis in these countries.

Hepatitis B Virus Blocks the CRE/CREB Complex and Prevents TLR9 Transcription and Function in Human B Cells

Effective B cell responses such as cytokine secretion, proliferation, and Ab-specific responses are essential to clear hepatitis B virus (HBV) infection. However, HBV alters numerous immune pathways to persist in the host. B cell activity depends on activation of the innate sensor TLR9 by viral or bacterial DNA motifs. How HBV can deregulate B cell functions remains unknown. In this study, we show that HBV can enter and decrease TLR9 expression in human primary B cells. Using PBMCs from human blood donors, we show that TLR9 expression was reduced in all peripheral B cells subsets exposed to HBV. B cell function mediated by TLR9, but not TLR7, such as proliferation and proinflammatory cytokines secretion, were abrogated in the presence of HBV; however, global Ig secretion was not downregulated. Mechanistically, we show, using human myeloma B cell line RPMI 8226, that the surface Ag hepatitis B surface Ag was responsible for TLR9 dysfunction. hepatitis B surface Ag suppressed the phosphorylation and thus the activation of the transcription factor CREB, preventing TLR9 promoter activity. Finally, we corroborated our in vitro findings in a cohort of chronic HBV carriers and found that TLR9 expression and function were significantly suppressed. The effect of HBV on TLR9 activity in B cells gives insights into oncoviral immune escape strategies, providing knowledge to develop novel immunotherapeutic approaches in chronic HBV-carrier patients.