Geographical distribution of the incidence of gastric cancer in Bhutan

Population-level cancer screening and cancer care in Bhutan, 2020-2023: a review

Screening of cancers is an important intervention in reducing the incidence and mortality related to cancers. Bhutan is one small country that is witnessing an increasing incidence and mortality related to cancers. The government implemented a time-bound population-level screening for gastric, cervical and breast cancers from 2020 to 2023 with an overall coverage of 91.2% of the eligible population. Among 370,225 individuals screened for H pylori, 32.4% tested positive; among 53,182 who underwent upper gastrointestinal endoscopy and biopsy, 255 (0.07%) had gastric cancer. Among 10,749 tested for HPV DNA, 9.3% were positive; among 9887 evaluated with colposcopy and biopsy, 154 (0.13%) had cervical cancer. For breast cancer screening, 72,283 underwent clinical breast examination, 845 mammography and cancer was detected in 73 (0.10%) individuals. In this article, we review how Bhutan implemented a population-level cancer screening programme with on boarding of multiple stakeholders and the participation of people across all districts.

Stomach Cancer Screening Services of Bhutan

Stomach cancer is a common public health problem in South East Asia including Bhutan. Chronic infection with Helicobacter pylori is regarded as the principal cause of stomach cancer. Herein, we present the incidence of stomach cancer in Bhutan for eight years (from 2014 to 2021). We also discuss the steps taken for the prevention and early detection of stomach cancer.

Epidemiology Helicobacter pylori infection in children in the Tyva Republic (Russia)

BACKGROUND

Tyva Republic is a small mountainous area at the geographical center of Asia in southern Siberia, with a high incidence of gastric cancer.

AIM

We examined the prevalence of H. pylori and associated risk factors among children in Tyva.

METHODS

Cross-sectional study was conducted among Tuvan children who had upper gastrointestinal symptoms and underwent upper gastroscopy with gastric biopsies. Informed consent was obtained from the parents and assent from the children. Demographic information, ethnicity, parents' education and employment status, and family size were collected. H. pylori infection was diagnosed by histologic examination.

RESULTS

There were 270 children between the ages 7 and 17 years (mean 13.4 ± 2.7); 64% girls; 147e Tuvan and 123 Caucasians. The overall prevalence of H. pylori was high and similar between boys and girls (55 vs. 57%, respectively, p = 0.42). The infection was highest in Tuvan children (67%. vs. 43%, respectively (OR = 2.4; 95%CI = 1.9.4-3), p = 0.05. H. pylori prevalence increased with age from 44% among 7 to 10 years and 64% among those 14 to 17 (OR = 3.0; 95%CI = 1.6-5.8), p = 0.0.005; the pattern was consistent among both ethnic groups. The prevalence of the infection among Caucasian children was inversely correlated with the level of mother's education (44%, vs. 61%) (i.e., for with and without a college education the OR = 2.3; 95%CI = 1.2-3.7), p = 0.02. Neither the total number of children nor adults living in the same household correlated with H. pylori prevalence.

CONCLUSIONS

Strategies to reduce the incidence of gastric cancer in Tyva will need to start in childhood.

Population-based study of Helicobacter pylori infection and antibiotic resistance in Bhutan

OBJECTIVES

Bhutan suffers from a high prevalence of Helicobacter pylori (H. pylori) infection and gastric cancer-related mortality. In preparation for a countrywide H. pylori eradication program, the antibiotic resistance patterns of H. pylori infection were surveyed in different geographical regions.

METHODS

Dyspeptic patients in 6 districts including Thimphu, Punakha, Wangdue, Trongsa, Bumthang, and Haa underwent upper gastrointestinal endoscopy during GASTROCAMP and were enrolled between December 2010 and April 2015. Gastric biopsies were obtained for rapid urease test, histopathology, and H. pylori culture. Antimicrobial susceptibility testing was later performed if the culture was positive.

RESULTS

A total of 1178 patients were surveyed. The overall H. pylori infection in Bhutan was 66.2%. Punakha had the highest prevalence of H. pylori infection (85.6%). Thimphu and Punakha (city areas) had higher prevalence of H. pylori infection than rural districts (73.5% vs 63.3%, OR=1.61, 95% CI 1.22-2.13, p=0.0008). There were 357 patients (30.3%) with positive H. pylori culture completed antimicrobial susceptibility testing. The mean age was 40.5 years with female predominance (57.1%). No amoxicillin resistant strains were found. Metronidazole resistance was 81% followed by levofloxacin resistance (8.1%). Clarithromycin (2%) and tetracycline (0.6%) resistance was rare except in Thimphu, the capital city (10%) vs 0% in rural areas, p<0.001. The metronidazole resistance rate remained stable at approximately 80% during the past 5 years of study. Levofloxacin-resistant strains gradually rose from 5.3% in 2010 to 9.9% in 2015.

CONCLUSIONS

Bhutan had a high prevalence of H. pylori infection. Metronidazole resistance was extremely high, whereas clarithromycin resistance was quite low in this specific area. Antibiotic resistance pattern could be good evidence for guiding a proper treatment regimen for H. pylori infection in Bhutan.

Efficacy of Omeprazole, Tetracycline, and 4 Times Daily Dosing of Amoxicillin in Helicobacter pylori Eradication in Limited Resource Area in Bhutan: A Prospective Randomized Trial (BHUTAN Study)

Backgrourd:

H. pylori-associated gastric cancer is the first cancer-related death in Bhutan. Effective regimen for H. pylori eradication is essential to reduce risk of developing gastric cancer. Clarithromycin is not widely used in this limited resource country. Aim of this study was to evaluate proper regimen and prevalence of antibiotic resistance pattern for H. pylori eradication in Bhutan.

Methods:

Five hundred and forty-six patients underwent gastroscopy during GASTROCAMP between October 2014 and April 2015 in Bhutan and 77 patients were enrolled. Four gastric biopsies were obtained for rapid urease test, histopathology, H. pylori culture with Epsilometer test. All H. pylori-positive patients were randomized to receive either 7-day or 14-day of 500 mg amoxicillin four times daily, 500 mg tetracycline four times daily, and 20 mg omeprazole twice daily.

Results:

Seventy-seven subjects were enrolled (54 females, 23 males, mean age = 45.4 years). Of 77 patients, 52 (67.5%) received 7-day regimen while 25 (32.5%) had 14-day regimen. Prevalence of H. pylori was 38.2%. Antibiotic resistance was 80.0% for metronidazole, 11.1% for levofloxacin and no resistance seen in amoxicillin, tetracycline and clarithromycin. Overall eradication rates of 7-day and 14-day regimens were 51.9% and 80.0%, p = 0.02. Female and age ≥40 years had significantly higher eradication rate when receiving 14-day compared to 7-day regimen (94.1% vs. 45.9%, OR = 18.82; 95% CI 2.26-157.02, p = 0.0007 and 86.7% vs. 50.0%, OR = 6.50; 95% CI 1.25-33.91, p = 0.02, respectively).

Conclusions:

Fourteen-day regimen might be an acceptable regimen for H. pylori eradication in limited resource area such as Bhutan. Female and age ≥40 years should receive longer duration of treatment. This 14-day regimen could at least reduce the risk of developing H. pylori-associated diseases especially peptic ulcer with complications and gastric cancer which lead to many deaths in Bhutan.

Plasma membrane Ca2+-permeable channels and sodium/calcium exchangers in tumorigenesis and tumor development of the upper gastrointestinal tract

The upper gastrointestinal (GI) tumors are multifactorial diseases associated with a combination of oncogenes and environmental factors. Currently, surgery, chemotherapy, radiotherapy and immunotherapy are relatively effective treatment options for the patients with these tumors. However, the asymptomatic phenotype of these tumors during the early stages poses as a significant limiting factor to diagnosis and often renders treatments ineffective. Therefore, new early diagnosis and effective therapy for upper GI tumors are urgently needed. Ca²⁺ is a pivotal intracellular second messenger and plays a crucial role in living cells by regulating several processes from cell division to death. The aberrant Ca²⁺ homeostasis is related to many human pathological conditions and diseases, including cancer, and thus the changes in the expression and function of plasma membrane Ca²⁺ permeable channels and sodium/calcium exchangers are frequently described in tumorigenesis and tumor development of the upper GI tract, including voltage-gated Ca²⁺ channels (VGCC), transient receptor potential (TRP) channels, store-operated channels (SOC) and Na⁺/Ca²⁺ exchanger (NCX). This review will summarize the current knowledge about plasma membrane Ca²⁺ permeable channels and sodium/calcium exchangers in the upper GI tumors and provide a synopsis of recent advancements on the role and involvement of these channels in upper GI tumors as well as a discussion of the possible strategies to target these channels and exchangers for diagnosis and therapy of the upper GI tumors.

TRP channels in gastric cancer: New hopes and clinical perspectives

Gastric cancer is a multifactorial disease associated with a combination of and environmental factors. Each year, one million new gastric cancer cases are diagnosed worldwide and two-thirds end up losing the battle with this devastating disease. Currently, surgery represents the only effective treatment option for patients with early stage tumors. However, the asymptomatic phenotype of this disease during the early stages poses as a significant limiting factor to diagnosis and often renders treatments ineffective. To address these issues, scientists are focusing on personalized medicine and discovering new ways to treat cancer patients. Emerging therapeutic options include the transient receptor potential (TRP) channels. Since their discovery, TRP channels have been shown to contribute significantly to the pathophysiology of various cancers, including gastric cancer. This review will summarize the current knowledge about gastric cancer and provide a synopsis of recent advancements on the role and involvement of TRP channels in gastric cancer as well as a discussion of the benefits of targeting TPR channel in the clinical management of gastric cancer.

Epidemiology of Helicobacter pylori infection in asymptomatic schoolchildren in Bhutan

AIM

Bhutan is a small mountainous country between Tibet and India with relatively homogenous population. According to the World Health Organization, gastric cancer is the most frequent cause of cancer death in Bhutan. This study examined the prevalence of Helicobacter pylori among children in Bhutan with emphasis on water source and living conditions.

METHODS

A cross-sectional sero-epidemiologic study was conducted among schoolchildren who attended public schools in Thimphu, Bhutan. Between 2015 and 2016, blood samples from schoolchildren were collected after obtaining an informed consent from the school management and the children's parents. Demographic information, parents' education, family size living in the same household, and aspects of household environment including type of latrines, boiling drinking water were collected. All serum samples were tested for H. pylori immunoglobulin G (IgG) by commercial ELISA kits.

RESULTS

There were 327 children between 4 and 19 years of age participated, 44% boys, mean age = 13.6 ± 3 years. The overall prevalence of H. pylori was 66% with no difference between boys and girls (66 vs 64%, respectively), P = .42. H. pylori prevalence was 75% among both 4-7 and 15-19 years and not statically different from that of the 8-10 or 11-14 age groups (59% and 63%, respectively), P = .1. H. pylori prevalence was inversely correlated with the level of mother's education (70% vs 55%) for those without and with a college education, respectively (OR = 2.3; 95%CI = 0.9-1.7), P = .08. The total number of people living in the same household did not correlate with H. pylori sero-prevalence, but households had less than 3 children had lower prevalence than those with 3 or more children (62% vs 71%, respectively OR = 1.7, 95% CI = [1.0-2.6], P = .05).

CONCLUSIONS

H. pylori infection is prevalent among all age group children in Bhutan. The results suggest that transmission of H. pylori is related to personal care practices that directly correlate with the mothers' education and crowded living condition with children. Our results are important to developing prevention strategies for gastric cancer in Bhutan.