Gastric cancer research in Mexico: A public health priority

Impact of surgical resection on the survival in Mexican patients with gastric cancer: A meta-analysis and systematic review

BACKGROUND

Gastric cancer (GC) is one of the most frequent cancer types in Mexico. The primary method used as a treatment is surgical resection. The role of surgery in increasing survival is controversial. This study aimed to determine whether surgical resection increases the survival of patients with GC in a Mexican population.

METHODS

A systematic review of literature searches (Evidence-based MEDLINE/PubMed, Web of Science, Cochrane Library, and SciELO) and meta-analysis were performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria. The published articles from 2000 to the current time were divided into cross-sectional and randomized studies. The inclusion criteria were survival, surgical resections, patients treated in Mexico, and primary GC. The effect estimation was calculated using the risk ratio (RR). The random-effects model and a confidence interval (CI) of 95% were used.

RESULTS

The RR of the pooled studies was 1.09 (95% CI, 0.71-1.67). RR of 0.82 (95% CI, 0.63-1.07) was obtained in cross-sectional studies, and randomized studies showed a RR of 2.08 (95% CI, 0.25-17.07).

CONCLUSION

This work is the first systematic study that assesses the role of surgery on the survival of patients with GC in the Mexican population, the results showed that surgical resection did not improve survival in patients with GC.

Capsaicin and cancer: Guilty as charged or innocent until proven guilty?

With an estimated 2 billion chili pepper connoisseurs worldwide, the human exposure to capsaicin is enormous. Therefore, the question whether nutritional capsaicin is a cancer causing or cancer preventive agent is of utmost importance. The gamut of human epidemiology studies suggests that capsaicin in modest, "restaurant-like" doses is not only safe to eat, but it may even provide health benefits, such as lower cancer-related death rate. Very "hot" food is, however, probably better avoided. Importantly, no increased cancer risk was reported in patients following topical (skin or intravesical) capsaicin therapy. Aberrant capsaicin receptor TRPV1 expression was noted in various cancers with potential implications for cancer therapy, diagnosis and prognostication. Indeed, capsaicin can kill cancer cells by a combination of on- and off-target mechanisms, though it remains unclear if this can be exploited for therapeutic purposes. The literature on capsaicin and cancer is vast and controversial. This review aims to find answers to questions that are relevant for our daily life and medical practice.

Lymph node retrieval in radical gastrectomy: the pathologist alone or the surgeon-pathologist team?

Introduction

Lymph node (LN) dissection is an important prognostic factor in gastric cancer. There is little information comparing the LN count depending on whether they are dissected in the operating room or in the pathology laboratory.

Aim

To establish if the LN count is greater in either of them.

Material and methods

From 2015 to 2017 all consecutive gastrectomies with D2 dissection were prospectively evaluated based in either of 2 protocols: One started in the operating room where the surgeon separated the LN levels and then submitted the entire adipose tissue with LNs (undissected) to pathology in separate containers; the pathologist dissected the LNs from the specimens. The second protocol consisted of sending the tissue/LNs to pathology as usual (adipose tissue and LN attached to the stomach).

Results

A total of 83 patients were analysed. The mean age was 58.4 years. The median number of LNs dissected in the protocol starting in the operating room was 56 (IQR: 37-74), whereas the pathology laboratory dissected a median of 39 LNs (IQR 26-53) (p = 0.005). The survival of cases dissected by both protocols were comparable (median survival of 48 and 43 months, p = 0.316).

Conclusions

The LN final count is significantly higher when LN levels are separated beforehand in the operating room compared to dissection only in pathology; however, this does not impact survival, perhaps because the number of dissected nodes in both groups is high and the quality of the surgery is good.

Microbiome-MX 2018: microbiota and microbiome opportunities in Mexico, a megadiverse country

A weekly conference series paired with lectures entitled "Microbiome-MX: exploring the Microbiota and Microbiome Research in Mexico" was organized to provide a multidisciplinary overview of the most recent research done in Mexico using high-throughput sequencing. Scientists and postgraduate students from several disciplines such as microbiology, bioinformatics, virology, immunology, nutrition, and medical genomics gathered to discuss state of the art in each of their respective subjects of expertise, as well as advances, applications and new opportunities on microbiota/microbiome research. In particular, high-throughput sequencing is a crucial tool to understand the challenges of a megadiverse developing country as Mexico, and moreover to know the scientific capital and capabilities available for collaboration. The conference series addressed three main topics important for Mexico: i) the complex role of microbiota in health and prevalent diseases such as obesity, diabetes, inflammatory bowel disease, tuberculosis, HIV, autoimmune diseases and gastric cancer; ii) the use of local, traditional and prehispanic products as pre/probiotics to modulate the microbiota and improve human health; and iii) the impact of the microbiota in shaping the biodiversity of economically important terrestrial and marine ecosystems. Herein, we summarize the contributions that Mexican microbiota/microbiome research is making to the global trends, describing the highlights of the conferences and lectures, rather than a review of the state-of-the-art of this research. This meeting report also presents the efforts of a multidisciplinary group of scientist to encourage collaborations and bringing this research field closer for younger generations.

Risk factors associated with gastric cancer in Mexico: education, breakfast and chili

BACKGROUND AND AIM

the aim of the study was to use a validated questionnaire to identify factors associated with the development of gastric cancer (GC) in the Mexican population.

METHODS

the study included cases and controls that were paired by sex and ± 10 years of age at diagnosis. In relation to cases, 46 patients with a confirmed histopathological diagnosis of adenocarcinoma-type GC, as reported in the hospital records, were selected, and 46 blood bank donors from the same hospital were included as controls. The previously validated Questionnaire to Find Factors Associated with Gastric Cancer (QUFA-GC©) was used to collect data. Odds ratio (OR) and 95% confidence interval (IC) were estimated via univariate analysis (paired OR). Multivariate analysis was performed by logistic regression. A decision tree was constructed using the J48 algorithm.

RESULTS

an association was found by univariate analysis between GC risk and a lack of formal education, having smoked for ≥ 10 years, eating rapidly, consuming very hot food and drinks, a non-suitable breakfast within two hours of waking, pickled food and capsaicin. In contrast, a protective association against GC was found with taking recreational exercise and consuming fresh fruit and vegetables. No association was found between the development of GC and having an income that reflected poverty, using a refrigerator, perception of the omission of breakfast and time period of alcoholism. In the final multivariate analysis model, having no formal education (OR = 17.47, 95% CI = 5.17-76.69), consuming a non-suitable breakfast within two hours of waking (OR = 8.99, 95% CI = 2.85-35.50) and the consumption of capsaicin ˃ 29.9 mg capsaicin per day (OR = 3.77, 95% CI = 1.21-13.11) were factors associated with GC.

CONCLUSIONS

an association was found by multivariate analysis between the presence of GC and education, type of breakfast and the consumption of capsaicin. These variables are susceptible to intervention and can be identified via the QUFA-GC

The fourth Mexican consensus on Helicobacter pylori

Important advances have been made since the last Mexican consensus on the diagnosis and treatment of Helicobacter pylori (H. pylori) infection was published in 2007. Therefore, the Asociación Mexicana de Gastroenterología summoned 20 experts to produce "The Fourth Mexican Consensus on Helicobacter pylori". From February to June 2017, 4 working groups were organized, a literature review was performed, and 3 voting rounds were carried out, resulting in the formulation of 32 statements for discussion and consensus. From the ensuing recommendations, it was striking that Mexico is a country with an intermediate-to-low risk for gastric cancer, despite having a high prevalence of H. pylori infection. It was also corroborated that peptic ulcer disease, premalignant lesions, and histories of gastric cancer and mucosa-associated lymphoid tissue lymphoma should be considered clear indications for eradication. The relation of H. pylori to dyspeptic symptoms continues to be controversial. Eradication triple therapy with amoxicillin, clarithromycin, and a proton pump inhibitor should no longer be considered first-line treatment, with the following 2 options proposed to take its place: quadruple therapy with bismuth (proton pump inhibitor, bismuth subcitrate, tetracycline, and metronidazole) and quadruple therapy without bismuth (proton pump inhibitor, amoxicillin, clarithromycin, and metronidazole). The need for antimicrobial sensitivity testing when 2 eradication treatments have failed was also established. Finally, the promotion of educational campaigns on the diagnosis and treatment of H. pylori for both primary care physicians and the general population were proposed.

Resources and Costs Associated with the Treatment of Advanced and Metastatic Gastric Cancer in the Mexican Public Sector: A Patient Chart Review

BACKGROUND

Little evidence is available on the management and cost of treating patients with advanced or metastatic gastric cancer (GC). This study evaluates patient characteristics, treatment patterns, and resource utilization for these patients in Mexico.

METHODS

Data were collected from three centers of investigation (tertiary level). Patients were ≥18 years of age, diagnosed between 1 January 2009 and 1 January 2015, had advanced or metastatic GC, received first-line fluoropyrimidine/platinum, and had ≥3 months follow-up after discontinuing first-line treatment. Data were summarized using descriptive statistics.

RESULTS

The study sample totaled 180. Patients' mean age was 57.2 years (±12.4) and 57.0% were male; 151 (83.9%) patients received second-line chemotherapy. A total of 16 and 19 regimens were identified in first- and second-line therapy. Of the sample, 51 (28.3%) received third-line therapy, and <10% received more than three lines of active chemotherapy. Supportive care received in first- and second-line chemotherapy, included pain interventions (12.2 and 7.9%), nutritional support (3.3 and 1.3%), radiotherapy (6.1 and 16.6%), and transfusions (13.3 and 10.6%), respectively. Using Mexican Institute of Social Security (IMSS) tariffs, the average total cost per patient-month in first- and second-line therapy was US$1230 [95% confidence interval (CI) 1034-1425] and US$1192 (95% CI 913-1471), respectively. Administration and acquisition of chemotherapy comprised the majority of costs.

CONCLUSIONS

This study shows considerable variation in first- and second-line chemotherapy regimens of patients with advanced or metastatic GC. Understanding GC treatment patterns in Mexico will help address unmet needs.

Gastric cancer in Latin America

Every year, cancer affects more than one million Latin Americans. The increasing incidence of cancer could be secondary to an aging population, westernization of life style, and urbanization. LA has among the highest incidence rates of gastric cancer, compared to other countries. In this review, different studies on gastric cancer and its relation with risks factors, such as infections, diet and life styles typical of LA, besides the different molecular alterations of that specific population (mainly at a genetic polymorphism level) are analyzed. An exhaustive research was made in PubMed, MEDLINE and Embase of the most relevant studies conducted in the last 27 years (1990-2017) in LA.

Best Practices and Practical Nuances in the Treatment of Gastric Cancer in High-Risk Global Areas

Gastric cancer is an aggressive disease that is very frequent in Latin America. The reasons for this increased incidence is not clear. Associated with the lack of minimum health care opportunities, lack of accurate statistics and reporting data beyond epidemiologic data, and raw nonreliable data, there is little known of the actual clinical course and treatment of these patients. Understanding epidemiologic data may allow us to encourage the adequate use and distribution of the meager resources that exist.

Polymorphisms in HLA-DQ genes, together with age, sex, and Helicobacter pylori infection, as potential biomarkers for the early diagnosis of gastric cancer

BACKGROUND

Polymorphisms in inflammation-related genes are factors associated with the development of gastroduodenal diseases in Helicobacter pylori-infected individuals.

MATERIALS AND METHODS

We aimed to analyze polymorphisms in HLA-DQ, together with other host and H. pylori variables as risk factors for precancerous and cancerous gastric lesions. 1052 individuals were studied, including nonatrophic gastritis (NAG), intestinal metaplasia (IM), gastric cancer (GC) or duodenal ulcer (DU) patients, and healthy volunteers.

RESULTS

Patients with alleles DQA*01:01 (OR 0.78), *01:02 (OR 0.29), *01:03 (OR 0.31), and DQB*02:01/02 (OR 0.40) showed a reduced risk for GC. A multivariate logistic regression analyses showed that patients with homozygote genotypes DQA1*03:01 (OR 7.27) and DQA1*04:01 (OR 8.99) and DQB1*05:01:01 (OR 12.04) were at significantly increased risk for GC. Multivariate analyses also demonstrated that age (OR>10.0) and gender (OR>2.0) were variables that influenced significantly the risk for GC, while H. pylori infection (OR>2.5) increased the risk for IM.

CONCLUSIONS

We identified HLA-DQ alleles associated with IM and GC, and confirm that age, sex, and H. pylori infection are variables that also influence the risk for disease. The use of multiple markers, HLA-DQ alleles, age, sex, and H. pylori infection may be useful biomarkers for the early diagnosis of patients with IM and GC.

Mortality trends and years of potential life lost from gastric cancer in Mexico, 2000-2012

BACKGROUND

In 2013 in Mexico, gastric cancer (GC) was the third leading cause of death from cancer in individuals 20 years of age or older. GC remains a public health problem in Mexico due to its high mortality and low survival rates, and the significantly lower quality of life of patients with this condition.

OBJECTIVES

The aims of this study were to determine mortality trends nationwide, by state and socioeconomic region, and to determine rates of age-adjusted years of potential life lost due to GC, by state and socioeconomic region, within the period of 2000-2012.

METHODS

Mortality records associated with GC for 2000-2012 were obtained from the National Health Information System of the Mexican Department of Health. Codes from the Tenth Revision of the International Classification of Diseases corresponding to the basic cause of death from GC were identified. Mortality and age-adjusted years of potential life lost rates, by state and socioeconomic region, were also calculated.

RESULTS

In Mexico, 69,107 individuals died from GC within the time frame of 2000-2012. The age-adjusted mortality rate per 100,000 inhabitants decreased from 7.5 to 5.6. The male:female ratio was 1.15:1.0. Chiapas had the highest death rate from GC (9.2, 95% CI 8.2-10.3 [2000] and 8.2, 95% CI 7.3-9 [2012]), as well as regions 1, 2, and 5. Chiapas and socioeconomic region 1 had the highest rate of years of potential life lost.

CONCLUSIONS

Using the world population age distribution as the standard, the age-adjusted mortality rate in Mexico per 100,000 inhabitants that died from GC decreased from 7.5 to 5.6 between 2000 and 2012. Chiapas and socioeconomic regions 1, 2, and 5 had the highest mortality from GC (Chiapas: 9.2, 95% CI 8.2-10.3 [2000] and 8.2, 95% CI 7.3-9 [2012], region 1: 5.5, 95% CI 5.2-5.9 [2000] and 5.3, 95% CI 4.9-5.7 [2012]; region 2: 5.3, 95% CI 5-5.6 [2000] and 5.4, 95% CI 5.1-5.8 [2012]; region 5: 6.1, 95% CI 5.6-6.6 [2000] and 4.6, 95% CI 4.2-5 [2012]). Chiapas and socioeconomic region 1 had the highest rate of years of potential life lost (Chiapas: 97.4 [2000] and 79.6 [2012] and region 1: 73.5 [2000] 65 [2012]).

Frequency of virulence genes in mixed infections with Helicobacter pylori strains from a Mexican population

BACKGROUND

Helicobacter pylori (H. pylori) is associated with gastroduodenal diseases. Virulence of clinical isolates is related to clinical outcome. Moreover, with microdiversity studies in clinical isolates from a single patient, but from a different origin (antrum or corpus), it is possible to demonstrate that there are simultaneous mixed infections.

AIMS

To genotype H. pylori strains with multiplex PCR, according to their clinical virulence, and in this manner know the frequency of each genotype and relate it to clinical outcome in order to prevent the development of severe diseases.

METHODS

A total of 210 patients with gastric alterations were studied. Virulence classification of H. pylori strains was carried out with multiplex PCR and 127 strains were identified as H. pylori by PCR (glmM and cagE). Genotype and clinical outcome were evaluated with the Fisher's exact test. In addition, RAPD-PCR was performed as a fingerprinting method to analyze mixed infections.

RESULTS

The cagA, vacAs1, and vacAm1 genes were detected in all the clinical isolates. Strains were classified as: type i, 40.15% (51/127); type ii, 22.04% (28/127); and type iii, 28.4% (36/127), but two new different genotypes were also detected: (1) babA2+, cagA+, vacAs1+, 6.29% (8/127) and (2) babA2+, cagA-, vacAs2/m2+, 3.14% (4/127). The cagE gene was detected in type i strains.

CONCLUSIONS

The Fisher's exact test did not support a significant association between clinical outcome and genotype. The main circulating genotypes in the Mexican population studied were: cagA+, vacAs1, and vacAm1. Multiplex PCR can be used as a screening test for H. pylori strains. Furthermore, the cagE gene is a good marker for identifying cag-PAI positive strains.

Complete Genome Sequence of Helicobacter pylori Strain 29CaP Isolated from a Mexican Patient with Gastric Cancer

Helicobacter pylori infection is a risk factor for the development of gastric cancer and other gastroduodenal diseases. We report here the complete genome sequence of H. pylori strain 29CaP, isolated from a Mexican patient with gastric cancer. The genomic data analysis revealed a cag-negative H. pylori strain that contains a prophage sequence.