Eradicating via C-urea breath screening to prevent gastric cancer in indigenous communities: a population-based study and development of a family index-case method.

Objective: Screening and eradication of help reduce disparities in the incidence of gastric cancer. We aimed to evaluate its acceptability and feasibility in the indigenous communities and develop a family index-case method to roll out this programme.

Design: We enrolled residents aged 20-60 years from Taiwanese indigenous communities to receive a course of test, treat, retest and re-treat initial treatment failures with the C-urea breath tests and four-drug antibiotic treatments. We also invited the family members of a participant (constituting an index case) to join the programme and evaluated whether the infection rate would be higher in the positive index cases.

Results: Between 24 September 2018 and 31 December 2021, 15 057 participants (8852 indigenous and 6205 non-indigenous) were enrolled, with a participation rate of 80.0% (15 057 of 18 821 invitees). The positivity rate was 44.1% (95% CI 43.3% to 44.9%). In the proof-of-concept study with 72 indigenous families (258 participants), family members of a positive index case had 1.98 times (95% CI 1.03 to 3.80) higher prevalence of than those of a negative index case. The results were replicated in the mass screening setting (1.95 times, 95% CI 1.61 to 2.36) when 1115 indigenous and 555 non-indigenous families were included (4157 participants). Of the 6643 testing positive, 5493 (82.6%) received treatment. According to intention-to-treat and per-protocol analyses, the eradication rates were 91.7% (89.1% to 94.3%) and 92.1% (89.2% to 95.0%), respectively, after one to two courses of treatment. The rate of adverse effects leading to treatment discontinuation was low at 1.2% (0.9% to 1.5%).

Conclusion: A high participation rate, a high eradication rate of and an efficient rollout method indicate that a primary prevention strategy is acceptable and feasible in indigenous communities.

Trial Registration Number: NCT03900910.