gms | German Medical Science

Introduction: Awareness is vital for cancer prevention. US studies show a strong link between web searches, as a digital trace data proxy for disease public awareness, and cancer incidence [1], [2]. In Germany, this relationship has not been investigated, thus far. Therefore, we study regional and temporal relationships between cancer incidence and web search volume (SV) and investigate the content of searches related to breast, cervical, colorectal, lung, prostate, and testicular cancer, brain tumors, and malignant melanoma in Germany.

Methods: Monthly aggregated data on cancer incidence and SV were analyzed for 107 district-free cities in Germany over a period of 18 months (from July 2018 to December 2019) using Google Ads Keyword Planner [3] and cancer incidence data from the Center for Cancer Registry Data at the Robert-Koch Institute [4]. Spearman’s correlation coefficient (r_S) were used to examine associations between cancer incidence and web SV; using repeated measures correlation (r_rm) we assessed time trends as well as differences across regions and malignancies. Search terms were categorized qualitatively.

Results: The analysis included 126,350 incident cancer diagnoses and 21,116,930 malignancy-related web searches (of 12,759 keywords and phrases) recorded in 107 district-free cities in Germany. The frequency of malignancy-related web searches correlated with cancer incidence (r_S=0.88, P=.007), eg, breast cancer had more queries than the lower-incidence cervical cancer. Seasonally, incidence and searches followed similar patterns, peaking in spring and fall, except for melanoma. Correlations between entity incidence and searches (0.037≤r_rm≤0.208) varied regionally. Keywords mainly focused on diagnosis, symptoms, and general information, with variations between entities. In Germany, web searches correlated with regional and seasonal incidence, revealing differences between North/East and South/West.

Discussion: We find moderate but consistent positive associations between cancer incidence and SV for 8 malignancies in German district-free cities. Examining this relationship reveals areas with high disparity. Areas with low SV and high incidence could signify socially deprived spots with unmet information needs. Our investigation is a first step toward using web search information to understand German public awareness about cancer. These insights may help improve prevention strategies by identifying regional needs and assessing impact of awareness campaigns.

Competing interests: Hannah Wecker (HW), Stefanie Ziehfreund (SZ), and Ian Erhard (IE) have no conflicts of interest to declare. Daniel Maier (DM) received speaker honoraria from Free University Berlin and travel compensation from IQVIA. Fabienne A.U. Fox (FAUF) received travel compensation from IQVIA. Jörg Janne Vehreschild (JJV) has received personal fees from Merck / MSD, Gilead, Pfizer, Astellas Pharma, Basilea, German Centre for Infection Research (DZIF), University Hospital Freiburg/ Congress and Communication, Academy for Infectious Medicine, University Manchester, German Society for Infectious Diseases (DGI), Ärztekammer Nordrhein, University Hospital Aachen, Back Bay Strategies, German Society for Internal Medicine (DGIM), Shionogi, Molecular Health, Netzwerk Universitätsmedizin, Janssen, NordForsk, Biontech, APOGEPHA and grants from Merck / MSD, Gilead, Pfizer, Astellas Pharma, Basilea, German Centre for Infection Research (DZIF), German Federal Ministry of Education and Research (BMBF), Deutsches Zetrum für Luft- und Raumfahrt (DLR), University of Bristol, Rigshospitalet Copenhagen, Network University Medicine. Alexander Zink (AZ) has been an advisor and/or received speaker's honoraria and/or received grants and/or participated in clinical trials of the following companies: AbbVie, Almirall, Amgen, Beiersdorf Dermo Medical, Bencard Allergie, BMS, Celgene, Eli Lilly, GSK, Janssen Cilag, Leo Pharma, Miltenyi Biotec, Novartis, Pfizer, Sanofi-Aventis, Takeda Pharma, UCB Pharma.

The authors declare that an ethics committee vote is not required.

The contribution has already been published: 1. Deutscher Krebsforschungskongress, Heidelberg, 30.10.2023-01.11.2023. 2. Scientific Reports [5]