Our study revealed much higher Google search volumes for MG topics over the past 2 decades than for LCS and CTC. The average search frequency for LCS was only approximately one-tenth of that for MG, and CTC search volume was only one–twenty-fifth of MG search volume. LCS average search volumes increased from 2011 to 2023, while searches for MG and CTC plateaued. MG-related topics had the highest total monthly search volume, followed by those related to LCS and CTC. Frequently searched topics varied across modalities and included nearby screening locations, procedural details or associated pain, and eligibility criteria.

MG consistently exhibited higher levels of search interest compared with LCS or CTC, possibly reflecting the longer history of MG and various longstanding initiatives focused on breast screening and women’s health [25,26]. Despite the higher absolute mortality for lung cancer than for breast cancer globally, search volumes for topics related to LCS have remained much lower than those for MG, although LCS search volumes have experienced an uptrend since 2011, when the National Lung Screening Trial was published [3]. MG was first established in 1913 and fully adopted in the 1970s [25], in contrast to low-dose CT for LCS, which gained widespread recognition in 2011. The early peak of interest in LCS in the 2004‐2006 period coincides with attention generated by early CT LCS programs, followed by a decline in interest until 2011 [27,28]. The relative search volumes for CTC have been persistently low over the last 2 decades, especially compared with MG (2%). While CTC is recognized by the national medical societies and formal guidelines of several countries as a viable screening option [29-31], other organizations have raised concerns regarding the strength of evidence supporting CTC or cost-effectiveness compared with colonoscopy [32,33]. The low search volumes might reflect a lack of awareness or desire for this screening option among the public.

Our topic analysis of recent volumes for queries related to image-based screening techniques showed both similarities and differences across imaging modalities. For example, in the case of MG, a substantial portion of searches (60,850/253,810, 24%) involved the nearest screening center, a topic with substantial although lower percentages of search volumes for LCS (750/11,150, 7%) and CTC (230/5590, 4%), highlighting a possible target of increased or more effective publicity. A relatively high volume of searches related to procedural aspects of CTC (1380/5590, 25%) may suggest a relative unfamiliarity with details of this specific imaging modality. A common topic of searches was potential procedural discomfort or pain in MG (28,970/253,810, 11%), with a lower percentage for CTC (220/5590, 1%), suggesting an opportunity for providers to better address procedural comfort that might otherwise decrease screening uptake. Cost or insurance coverage for screening was in the top 10 most-searched topics for all 3 screening modalities but comprised a minority of searches in terms of percentage; although cost and coverage pose concerns for some individuals, it is notable that several other topics, such as the nearest screening locations, procedural pain, and eligibility criteria, had on average 2- to 3-fold higher search volumes. AI and deep learning were common search topics for LCS (1210/11,150, 11%) but were not common queries for MG or CTC; this is somewhat surprising, as AI in the form of computer-aided detection is commonly used in MG.

Previous research has examined internet search trends for cancer screening examinations. Snyder et al [20] examined Google search volume trends for cancer screening terms during the first stages of the COVID-19 pandemic, finding a temporary decline in searches for terms related to MG, LCS, colonoscopy, and pap smear. Rosenkrantz and Prabhu [22] performed a Google Trends analysis of the relative frequency of Google searches for MG, LCS, CTC, and prostate magnetic resonance imaging from 2004 to 2014, finding a slight progressive decline over the decade in searches for MG, a decrease from 2004 to 2010 in searches for LCS, followed by a persistent increase beginning in 2011, and an overall decade-long decline in searches for CTC; these findings are consistent with our analysis, although we show that searches for LCS continued to rise from 2014 to 2023 and that searches for MG and CTC have continued to plateau. Our analysis also has the advantage of comparing both the relative and absolute volumes of searches across modalities (MG, LCS, and CTC) instead of relying solely on relative search volumes, showing that searches related to MG greatly exceeded those related to LCS and CTC.

A variety of other methods have been used to assess public interest in and knowledge of cancer screening, including interviews, focus group discussions, questionnaires, and news coverage analysis [10,34,35]. Raju et al’s [34] survey of LCS-eligible individuals who chose not to participate in screening found that 19% of individuals had concerns about the distance to the screening site, and 14% of individuals had concerns about insurance coverage, recalling some of the frequent search topics for LCS in our study. In a Google News analysis of news coverage of MG from 2006 to 2015 [21], the most frequently covered topics included screening MG controversies (29%), new breast imaging technology (23%), imaging of dense breasts (11%), and public screening initiatives (11%), topics that were not among the most common MG searches in our study.

To our knowledge, our study is the first to use internet search engine data to gauge both general and topic-level public interest across imaging-based screening modalities by providing both relative search frequencies and estimates of absolute search volumes. We examined 2 decades of Google search volumes across 3 key imaging-based cancer screening examinations and documented the most common themes of recent related search queries.

Our study had several limitations. First, there are limitations inherent in any method of search volume estimation. Google Trends reports search data in relative terms and may report a value of 0 when search frequencies are low. For topic analysis, we captured data representing a snapshot of queries over a year, while queries may change over time. Search volumes were also estimated through a proprietary tool that uses Google autocomplete as a proxy for search volumes, as actual absolute search volumes are not available from Google Trends. However, our goal was not to measure exact search volumes but rather to analyze and compare trends across modalities and to discern the topics of the most frequent searches. Second, the analysis of thematic categories is intrinsically subjective; we attempted to mitigate this by using 2 observers, with final decisions rendered by consensus. Third, we analyzed worldwide Google searches in English and did not perform a country or region-specific analysis; while such comparative analyses are potentially of interest because of differences in screening guidelines and behavior across countries, our main objectives were to provide a general and comprehensive analysis of search interest across modalities and to determine the main topics of search queries. Future studies may incorporate comparisons of search queries across countries. Finally, internet search volumes may not directly translate to individual concerns, real-world behaviors, or screening uptake; however, individuals frequently turn to the internet as a source of medical information [16], and internet searches have often been used as a proxy of public interest in a wide variety of health-related topics [17-20,22].