Abstract / Summary
Introduction Gastric cancer remains a major cause of morbidity and mortality in Japan. Digital search data such as Google Trends have been increasingly used to capture population-level health information–seeking behavior and may complement traditional surveillance systems. However, it remains unclear whether gastric cancer awareness campaigns are associated with measurable changes in online search activity and whether search interest reflects regional disease burden.Aim This study aimed to evaluate changes in national online search activity during the Gastric Cancer Awareness Month and to assess whether prefecture-level search volume was associated with regional gastric cancer incidence.Methods We conducted a population-level ecological study using publicly available Google Trends data for Japan from 2012 to 2021. Interrupted time series analysis was applied to evaluate monthly changes in search activity during the awareness month. Prefecture-level associations between annual mean search volume and age-standardized gastric cancer incidence were examined for 2017–2021.Results At the national level, search activity related to gastric cancer remained relatively stable, with no significant changes in level or trend during the awareness month. In contrast, prefecture-level analyses revealed positive associations between search volume and gastric cancer incidence, although several high-burden regions showed comparatively low search interest.Conclusions The awareness month was not associated with measurable increases in online search activity at the national level, suggesting limited population response to current campaigns. Google Trends data can complement traditional surveillance by identifying regions with low public attention despite high disease burden, thereby supporting more targeted and data-informed cancer communication strategies.