Digital information-seeking behavior has emerged as a potential proxy for awareness and engagement with health services. Google Trends provides anonymized, real-time data that may reflect public interest in diseases and preventive services. However, how these digital signals relate to cancer burden across different socioeconomic contexts remains insufficiently explored.To assess the ecological association between online search interest for selected cancers and screening tests and corresponding cancer incidence and mortality across Human Development Index (HDI) groups.An ecological study was conducted including 185 countries, classified into four HDI groups (low, medium, high, very high). Google Trends relative search volumes (RSV) were retrieved for terms related to breast, prostate, colorectal, and cervical cancers, and associated screening tests (mammography, prostate-specific antigen, colonoscopy, Pap smear, and human papillomavirus). Additional analyses included stomach, pancreatic, lung, and liver cancers, for which no established population screening programs exist. Spearman correlation coefficients were calculated to examine relationships between RSV values and cancer incidence and mortality rates.Screening-related searches demonstrated stronger positive correlations with incidence and mortality in higher HDI countries. Cervical cancer–related searches showed positive correlations with disease burden in high and medium HDI groups, while significant associations persisted for cervical cancer in low HDI countries. Cancers without established screening programs generally showed no correlations with epidemiological indicators, except for modest associations in very high HDI countries and moderate correlations for liver cancer in low HDI settings. Increasing HDI was associated with higher burdens of colorectal, breast, pancreatic, and lung cancers, whereas inverse patterns were observed for cervical and liver cancers.Online information-seeking behavior shows context-dependent associations with cancer epidemiology. However the findings suggest that digital search behavior reflects not only disease burden but also screening availability, health literacy, and access to care. Stronger correlations in high HDI settings likely reflect institutionalized screening programs, while persistent cervical cancer correlations in lower HDI countries may indicate unmet preventive needs, particularly among socioeconomically disadvantaged women.Google Trends may serve as a complementary digital indicator to inform public health surveillance and primary care–oriented cancer prevention strategies when interpreted within socioeconomic frameworks.