Samantha Morais

Trends in gastric cancer mortality and in the prevalence of Helicobacter pylori infection in Portugal.

Portugal has the highest gastric cancer mortality rates in Western Europe, along with high prevalences of Helicobacter pylori infection. Monitoring their trends is essential to predict the burden of this cancer. We aimed to quantify time trends in gastric cancer mortality in Portugal and in each administrative region, and to compute short-term predictions, as well as to describe the prevalence of H. pylori infection, through a systematic review. Joinpoint analyses were used to identify significant changes in sex-specific trends in gastric cancer age-standardized mortality rates (ASMR) and to estimate annual percent changes (APC). The most recent trends were considered to compute estimates up to 2020 by adjusting Poisson regression models. We searched PubMed and IndexRMP to identify studies carried out in Portugal reporting the prevalence of H. pylori. Gastric cancer mortality has been decreasing in Portugal since 1971 in men (from ASMR=55.3/100 000; APC=−2.4, 95% confidence interval: −2.5 to −2.3) and since 1970 in women (from ASMR=28.0/100 000; APC=−2.8, 95% confidence interval: −2.9 to −2.7), although large regional differences were observed. Predicted ASMR for 2015 and 2020 were 18.8/100 000 and 16.7/100 000 for men and 8.5/100 000 and 7.4/100 000 for women, respectively. The prevalence of H. pylori varied from almost 5% at 0.5–2 years to just over 90% at 70 years or more. No consistent variation was observed since the 1990s. The downward trends in mortality rates are expected to remain in the next decades. The high prevalence of H. pylori infection across age groups and studies from different periods shows a large potential for decrease in the burden of gastric cancer in Portugal.

Sex-differences in the prevalence of Helicobacter pylori infection in pediatric and adult populations: Systematic review and meta-analysis of 244 studies

BACKGROUND The main outcome of Helicobacter pylori infection, i.e. gastric cancer, is more frequent in men, but there is no comprehensive synthesis of the evidence on a potential role of sex in the acquisition and/or persistence of infection. AIMS To quantify the association between sex and H. pylori infection in pediatric and adult populations, through systematic review and meta-analysis. METHODS PubMed® was searched, from inception to September 2015, to identify population-based studies reporting the prevalence and/or incidence of H. pylori infection in both sexes. Odds ratios (OR) or data to compute them were extracted; adjusted estimates were preferred, whenever available. The DerSimonian and Laird method was used to compute summary estimates and respective 95% confidence intervals (95%CI), separately for children and adults. RESULTS Among a total of 244 studies, mostly cross-sectional, male sex was associated with a greater prevalence of H. pylori infection, both in children (102 studies, OR=1.06, 95%CI: 1.01, 1.12, I2=43.7%) and adults (169 studies, OR=1.12, 95%CI: 1.09, 1.15, I2=68.5%). An underrepresentation of studies showing a negative association between male sex and infection was observed (Eggers test: p=0.006). CONCLUSIONS Although further research is needed to understand the mechanisms by which sex may influence the acquisition and/or persistence of infection, our results support a small contribution of sex differences in the prevalence of infection to the male predominance of H. pylori-related outcomes, including gastric cancer.

Trends in thyroid cancer incidence and mortality in Portugal.

The objective was to quantify thyroid cancer incidence and mortality trends in Portugal. The number of thyroid cancer cases and incidence rates were retrieved from the Regional Cancer Registries for the period 1989–2011. The number of deaths and mortality rates were obtained from the WHO cancer mortality database (1988–2003 and 2007–2012) and Statistics Portugal (2004–2006; 1988–2012 by region). Joinpoint regression of the standardized incidence and mortality rates was performed. A significant, rapid and continued increase in incidence was observed for both sexes in each of the Regional Cancer Registries, with annual per cent changes (APCs) ranging between 2 and 9. Incidence in Portuguese women is higher than estimates for the world and Europe. Mortality decreased for women (APC: −1.5), with the greatest decrease in the North, and increased marginally for men (APC: +0.2), with a greater increase in the South. The significant increases in incidence in Portugal are predominantly because of the increase in incidence among women from the North. These trends, combined with an overall low mortality and high 5-year relative survival, raise concerns on the extent to which overdiagnosis may be taking place. Further research is needed, quantifying the importance of the most likely determinants of these trends as well as the extent and potentially deleterious effects of overdiagnosis and overtreatment in the Portuguese setting.

Tobacco smoking and intestinal metaplasia: Systematic review and meta-analysis

BACKGROUND The evaluation of specific risk factors for early endpoints in the gastric carcinogenesis pathway may further contribute to the understanding of gastric cancer aetiology. AIMS To quantify the relation between smoking and intestinal metaplasia through systematic review and meta-analysis. METHODS Articles providing data on the association between smoking and intestinal metaplasia were identified in PubMed(®), Scopus(®) and Web of Science™, searched until April 2014, and through backward citation tracking. Summary odds ratio estimates and 95% confidence intervals were computed using the DerSimonian and Laird method. Heterogeneity was quantitatively assessed using the I(2) statistic. RESULTS A total of 32 articles were included in this systematic review and 19 provided data for meta-analysis. Smoking was defined as ever vs. never (crude estimates, six studies, summary odds ratio=1.54, 95% confidence interval: 1.12-2.12, I(2)=67.4%; adjusted estimates, seven studies, summary odds ratio=1.26, 95% confidence interval: 0.98-1.61, I(2)=65.0%) and current vs. non-smokers (crude estimates, seven studies, summary odds ratio=1.27, 95% confidence interval: 0.88-1.84, I(2)=73.4%; adjusted estimates, two studies, summary odds ratio 1.49, 95% confidence interval: 0.99-2.25, I(2)=0.0%). CONCLUSION The weak and non-statistically significant association found through meta-analysis of the available evidence does not confirm smoking as an independent risk factor for intestinal metaplasia.

Worldwide burden of gastric cancer in 2012 that could have been prevented by increasing fruit and vegetable intake and predictions for 2025.

The regional and temporal variation in patterns of fruit and vegetable intake contributes to differences in the impact on gastric cancer burden across regions and over the years. We aimed to estimate the proportion and absolute number of gastric cancer cases that could have been prevented in 2012 with an increase in fruit and vegetable intake up to the levels defined by the Global Burden of Disease as the theoretical minimum-risk exposure distribution (300 and 400 g/d, respectively), as well as the corresponding figures expected for 2025. Preventable fractions (PF) were computed for 161 countries, using data on fruit and vegetable availability in 1997 and 2010 and published estimates of the magnitude of the association between fruit and vegetable intake and gastric cancer, assuming a time lag of approximately 15 years. Countries classified as very high Human Development Index (HDI) presented median PF in 2012 much lower than low-HDI countries for both fruits (3·0 v. 10·2%, P<0·001) and vegetables (6·0 v. 11·9%, P<0·001). For vegetables only, PF significantly decreased until 2025 in most settings; however, this corresponded to a reduction in the absolute number of preventable gastric cancer cases in less than half of the countries. Increasing fruit and vegetable intake would allow preventing a relatively high proportion of gastric cancer cases, mostly in developing countries. Although declines in PF are predicted in the near future, changes in order to achieve healthier lifestyles may be insufficient to overcome the load of demographic variation to further reduce the gastric cancer burden.

Contemporary migration patterns in the prevalence of Helicobacter pylori infection: A systematic review

A rapid growth in the number of international migrants over the past years has occurred with most traveling to more affluent settings. As Helicobacter pylori infects over half of the adult population and its prevalence is higher in developing countries, understanding the prevalence of infection in migrants can provide insight into future trends in the burden and management of infection. We aimed to describe the prevalence of H. pylori among migrants through a systematic literature review.

Risk of second primary cancers among patients with a first primary gastric cancer: A population-based study in North Portugal

BACKGROUND The growing number of incident cases of gastric cancer along with improved survival result in a rising population of survivors at risk of second primary cancers (SPC). We estimated the cumulative incidence of metachronous (diagnosed >2months after first primary cancer [FPC]) SPC in gastric FPC patients and compared the incidence of metachronous SPC with that expected in the general population. METHODS A cohort of gastric FPC patients from the North Region Cancer Registry of Portugal, diagnosed in 2000-2006 (n=7427) was followed to 31 December 2010 for synchronous and metachronous SPCs. Cumulative incidence of metachronous SPCs taking into account death as a competing event and standardized incidence ratios (SIR) of metachronous SPCs were estimated. RESULTS Overall, 331 (4.5%) patients developed an SPC (26.9% synchronous and 73.1% metachronous). Over half of the SPCs occurred in digestive organs. Among men, the most frequent were colon, prostate, and trachea, bronchus and lung; in women, colon, breast and thyroid were the most common. The 10-year cumulative incidence of metachronous SPC for males was 5.7% and for females 3.5%. The SIR for all cancers was 1.30 in males and 1.20 in females. Among both sexes, significantly higher SIRs were observed for cancers of the oesophagus (males: 4.99; females: 8.03), small intestine (males: 11.04; females: 13.09) and colon (males: 2.42; females: 2.58). CONCLUSIONS Patients with a gastric FPC were found to be at increased risk of developing SPC, mainly in digestive organs, when compared to the general population. Close surveillance of these patients may allow early detection of SPC.

The occupational risk of Helicobacter pylori infection: a systematic review

PurposeThe aim of this systematic review was to describe the prevalence of Helicobacter pylori infection in specific occupational groups and to compare them with the general population.MethodsWe searched PubMed® to identify original studies reporting the prevalence of H. pylori infection in occupational groups. The differences between occupational groups and the general population were analyzed taking into account the direction and statistical significance of the differences observed when comparing each occupational group with a reference group (either recruited in the same study or using an external comparator).ResultsA total of 98 studies addressing the prevalence of H. pylori infection in occupational groups were included in the systematic review. Overall, health professionals showed a significantly higher prevalence of H. pylori infection than the general population, especially among those working at gastrointestinal units. Similar results were found in subjects involved in agricultural, forestry and fishery, as well as in sewage workers, miners, and workers at institutions for the intellectually disabled, although differences were less pronounced.ConclusionsOur results show an occupational risk of H. pylori infection supporting the role of oral–oral, fecal–oral, and zoonotic transmission. Studies comparing specific occupational groups with adequate comparators may contribute to better identify groups at higher risk of infection. The recognition of this infection as an occupational disease would result in early detection and treatment, as well as prevention and control of its transmission in workplaces.

Projections in Breast and Lung Cancer Mortality among Women: A Bayesian Analysis of 52 Countries Worldwide

Among women, lung cancer mortality rates have surpassed those for breast cancer in several countries. This reflects the breast cancer mortality declines due to access to screening and effective treatment alongside the entrance of certain countries in stages of the tobacco epidemic in which smoking becomes more prevalent in women. In this study, we project lung and breast cancer mortality until 2030 in 52 countries. Cancer mortality data were obtained from the WHO Mortality Database. Age-standardized mortality rates (ASMR), per 100,000, were calculated (direct method) for 2008 to 2014 and projected for the years 2015, 2020, 2025, and 2030 using a Bayesian log-linear Poisson model. In 52 countries studied around the world, between 2015 and 2030, the median ASMR are projected to increase for lung cancer, from 11.2 to 16.0, whereas declines are expected for breast cancer, from 16.1 to 14.7. In the same period, the ASMR will decrease in 36 countries for breast cancer and in 15 countries for lung cancer. In half of the countries analyzed, and in nearly three quarters of those classified as high-income countries, the ASMR for lung cancer has already surpassed or will surpass the breast cancer ASMR before 2030. The mortality for lung and breast cancer is higher in high-income countries than in middle-income countries; lung cancer mortality is lower in the latter because the tobacco epidemic is not yet widespread. Due to these observed characteristics of lung cancer, primary prevention should still be a key factor to decrease lung cancer mortality.Significance: The mortality for lung and breast cancer is projected to be higher in high-income countries than in middle-income countries, where lung cancer mortality is expected to surpass breast cancer mortality before 2030. Cancer Res; 78(15); 4436-42. ©2018 AACR.

Alcohol intake and gastric cancer: Meta-analyses of published data versus individual participant data pooled analyses (StoP Project)

BACKGROUND Individual participant data pooled analyses allow access to non-published data and statistical reanalyses based on more homogeneous criteria than meta-analyses based on systematic reviews. We quantified the impact of publication-related biases and heterogeneity in data analysis and presentation in summary estimates of the association between alcohol drinking and gastric cancer. METHODS We compared estimates obtained from conventional meta-analyses, using only data available in published reports from studies that take part in the Stomach Cancer Pooling (StoP) Project, with individual participant data pooled analyses including the same studies. RESULTS A total of 22 studies from the StoP Project assessed the relation between alcohol intake and gastric cancer, 19 had specific data for levels of consumption and 18 according to cancer location; published reports addressing these associations were available from 18, 5 and 5 studies, respectively. The summary odds ratios [OR, (95%CI)] estimate obtained with published data for drinkers vs. non-drinkers was 10% higher than the one obtained with individual StoP data [18 vs. 22 studies: 1.21 (1.07-1.36) vs. 1.10 (0.99-1.23)] and more heterogeneous (I2: 63.6% vs 54.4%). In general, published data yielded less precise summary estimates (standard errors up to 2.6 times higher). Funnel plot analysis suggested publication bias. CONCLUSION Meta-analyses of the association between alcohol drinking and gastric cancer tended to overestimate the magnitude of the effects, possibly due to publication bias. Additionally, individual participant data pooled analyses yielded more precise estimates for different levels of exposure or cancer subtypes.