Mass eradication of Helicobacter pylori to reduce gastric cancer incidence and mortality: a long-term cohort study on Matsu Islands

Abstract

Objective: Although mass eradication of Helicobacter pylori has been proposed as a means to eliminate gastric cancer, its long-term effects remain unclear.

Design: Mass eradication of H. pylori infection was launched in 2004 and continued until 2018 for a high-risk Taiwanese population aged 30 years or older dwelling on Matsu Islands with prevalent H. pylori infection. Test positives for the ¹³C-urea breath test underwent eradication therapy. We evaluated the effectiveness of the mass eradication in reducing two main outcomes, incidence and mortality rates of gastric cancer, until the end of 2016 and 2018, respectively.

Results: After six rounds of mass screening and eradication, the coverage rate reached 85.5% (6512/7616). The referral rate for treatment was 93.5% (4286/4584). The prevalence rates of H. pylori fell from 64.2% to 15.0% with reinfection rates of less than 1% per person-year. The presence and severity of atrophic gastritis and intestinal metaplasia also decreased with time. Compared with the historical control period from 1995 to 2003, the effectiveness in reducing gastric cancer incidence and mortality during the chemoprevention period was 53% (95% CI 30% to 69%, p<0.001) and 25% (95% CI -14% to 51%, p=0.18), respectively. No significant changes were noted in the incidence rates of other digestive tract cancers or the antibiotic resistance rate of H. pylori.

Conclusion: Population-based eradication of H. pylori has significantly reduced gastric cancer incidence with no increase in the likelihood of adverse consequences. A significant reduction in mortality is likely to be achieved with a longer follow-up period.

Trial registration number: NCT00155389.

Keywords: cancer prevention; gastric cancer; helicobacter pylori.

Figure 1

Timeline of the gastric cancer prevention programme implemented on the Matsu Islands, Taiwan. EGD, oesophagogastroduodenoscopy; UBT, urea breath test.

Figure 2

Prevalence rates and reinfection rates of Helicobacter pylori (HP).

Figure 3

The presence and severity of premalignant gastric lesions according to the operative link for gastritis assessment of atrophic gastritis (OLGA) and operative link for gastritis assessment of intestinal metaplasia (OLGIM) grading systems. over 2004–2018, for the presence of atrophic gastritis and intestinal metaplasia (ie, grade ≥1), the prevalence rates declined from 55.9% to 15.9% and from 31.7% to 21.4%, respectively (both p<0.001). For advanced-stage atrophic gastritis and intestinal metaplasia (ie, grade 3 or 4), the prevalence rates declined from 7.1% to 0 and from 11.8% to 1.8%, respectively (both p<0.001).

Figure 4

Incidence rates of gastric cancer between 1995 and 2016, correlated with the start of the mass eradication programme in 2004. The dash line indicates the predicted trend to 2025. The Gamma-Poisson regression model was internally validated by using data on the incidence rate of gastric cancer between 1995 and 2003 with the goodness-of-fit test (χ²=4.95; p=0.84). The magnitude of risk reduction was determined by comparing the expected number of cases with the number observed during the chemoprevention period.

Figure 5

Rates of mortality from gastric cancer between 1995 and 2018, correlated with the start of the mass eradication programme in 2004. The dash line indicates the predicted trend to 2025. The Gamma-Poisson regression model was internally validated by using data on the mortality rate of gastric cancer between 1995 and 2003 with the goodness-of-fit test (χ²=3.88; p=0.92). The magnitude of mortality reduction was determined by comparing the expected number of cases with the number observed during the chemoprevention period.