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Cancer poses a significant burden on global public health []. In urology, bladder, kidney, and prostate cancers are the 3 primary genitourinary cancers contributing to the global burden of disease (GBD), with persistently high morbidity and mortality rates [,]. According to a GBD report from 2019, the annual global incidence rates of bladder, kidney, and prostate cancers have risen by 154.78%, 123.34%, and 169.11%, respectively, over the past 2 decades, making them the most prominent cancers in the field of urology [,]. In mainland China, the incidence rates of bladder, kidney, and prostate cancers in 2019 had doubled compared with 1990 and are projected to triple by 2030 [], with 192,390 cases of bladder cancer, 126,980 cases of kidney cancer, and 315,310 cases of prostate cancer. Therefore, precautionary measures are essential in addition to gathering information and assessing the disease burden using real-world data.
Infodemiology was defined as “The framework for an emerging set of public health informatics methods to analyze search, communication and publication behavior on the Internet.” It has been shown to effectively highlight public health issues, assess the impact of health care policies, and uncover public concerns during global pandemics, as well as in chronic and contagious diseases, along with related public acceptance [-]. Examining underlying trends in user behavior and the specific demands associated with major genitourinary cancers could potentially provide insights into regional health information–seeking behaviors and population-level interests.
Cancer imposes a significant burden on patients and their families, typically measured in terms of financial costs and clinical outcomes [,]. However, there is limited understanding of its broader impacts, such as public awareness, emotional well-being, and social participation. In China, previous studies have examined prevalent noncancer urological issues and their online visibility using data from the Baidu Index [,,], a tool that analyzes search behaviors to reflect public interest in health topics. While prior research has explored general cancer-related searches, these studies primarily focused on incidence correlations and population-level disparities across 28 cancer types [], offering limited insights into specific user demands or temporal and geographic patterns.
This study aims to address this gap by focusing on 3 major genitourinary cancers: bladder cancer, kidney cancer, and prostate cancer. Using Baidu Index data, we analyzed internet search trends, user needs, and associated geospatial and temporal patterns. By identifying search behaviors and topics of interest, we seek to provide actionable insights into public health awareness and address unmet needs, potentially contributing to the improvement and guidance of health care strategies.
Baidu (Baidu, Inc.), the leading search engine in mainland China, accounts for 92.1% of the search volume and 93.1% of user coverage []. Its analytics platform, Baidu Index, allows for tracking keyword popularity trends and analyzing related user demands [,,]. Comparable to Google’s platform on a global scale, Baidu has been validated as a reliable tool for studying online search trends and user behavior in infodemiology research within China [,].
This study primarily focuses on analyzing the temporal search trends of cancer-related terms associated with kidney, bladder, and prostate cancers. Based on defined criteria, these terms are characterized as compounds [], combining morphemes denoting a urological organ with those indicating tumor-related concepts. The key morphemes identified were (1) “肾脏” or “肾” (the kidney), (2) “膀胱” (the bladder), (3) “前列腺” (the prostate), and (4) “肿瘤” (the tumor). The Baidu Index platform automatically matched these combinations with all available search keywords, including synonyms and complex derivatives. Measures were implemented to prevent duplication and omissions, following approaches detailed in previous studies [,]. Synonyms and complex derivatives were screened and selected to minimize ambiguity and bias arising from language habits, as previously described [,]. All available search keywords related to these 3 cancer types were categorized based on their connotations and are listed in .
The Baidu Index platform consists of 3 key modules: (1) the search trend module, (2) the user demand module, and (3) the demographic portrait module. These modules enable the analysis of search demand from multiple perspectives, including popularity trends, topic-related concerns, and geodemographic features [,]. Search popularity is quantified using the Baidu Search Index (BSI), a key metric based on daily recorded search demand. With integrated data on location, gender, age, and other elements, trends and demographic profiles of the population can be visualized and retrieved [,]. Search trend data, available since 2011, were retrieved from the search trend module of the Baidu Index platform []. Data at both provincial and national scales were collected for the period from January 1, 2011, to July 31, 2023. The most recent data from the geodemographic and user demand modules were obtained from the user demand module on the Baidu Index official website [,].
Data Processing and Statistical AnalysisThe Baidu Index is a data-sharing platform that leverages extensive user behavior data to measure search trends. By tracking the frequency of unique keyword searches and their weighting within Baidu’s overall search volume, it provides a metric for keyword popularity. This study collected data on a daily, weekly, monthly, and yearly basis to capture a comprehensive view of cancer-related search patterns. Sequential plotting of BSI data for each term was conducted to illustrate trends in public interest. Changes in trends over time were analyzed using the Joinpoint Regression Model (program version 4.7.0.0; Statistical Research and Applications Branch, National Cancer Institute). This model, well-suited for time-series analysis of large data sets, identifies statistically significant shifts in trends. The annual percentage change (APC) was calculated to summarize yearly trends within specified intervals, measuring year-over-year percentage changes. The average APC (AAPC) was used to evaluate trends over extended periods, providing a more stable estimate of the overall trend direction and rate of change [,]. For each topic—bladder cancer, kidney cancer, and prostate cancer—the public demand trend was illustrated through sequentially plotted BSI data. Intergroup differences were analyzed using the Student t test and Kruskal-Wallis test, as appropriate. A P value of <.05 was considered statistically significant.
In the user demand section, the top 10 most frequently mentioned words related to each search keyword were listed weekly and sorted by cancer type. This allowed for the identification and analysis of the most prominent and commonly discussed topics for each cancer type. In line with previous findings, we used a 13-topic system to categorize user demand–related terms, helping to clarify users’ main concerns and implied intentions []. Aside from some random or off-topic terms, these categories were defined as follows: (1) complaint, (2) inquiry, (3) treatment and decision, (4) health issue, (5) diagnosis, (6) hospital and service, (7) symptom confirmation, (8) tests and examinations, (9) prognosis, (10) traditional Chinese medicine (TCM) complaint, (11) TCM inquiry, (12) TCM ingredient, and (13) TCM regimen.
All databases were constructed using Excel 2019 (Microsoft Corporation). The APC was calculated with the Joinpoint Regression Model, program version 4.7.0.0 (Statistical Research and Applications Branch, National Cancer Institute). Statistical analysis and figure creation were performed using Prism 9 for macOS (version 9.5.0 (525); GraphPad Software).
Ethical ConsiderationsWe used publicly available, anonymized data that can be accessed without special permissions. As the data are aggregated and publicly accessible, IRB approval or exemption was not required.
We identified and confirmed 39 valid search keywords on the Baidu Index platform. These keywords are theme-based synonyms and moderate derivative terms that convey specific motives or demands. Among these, 13 keywords pertained specifically to bladder cancer, while 15 and 11 keywords were related to kidney cancer and prostate cancer, respectively. For theme categorization, 4 topics were identified: (1) complaint, with 9 keywords; (2) inquiry, with 23 keywords; (3) treatment, with 4 keywords; and (4) prognosis, with 3 keywords. All available search keywords related to these 3 urological cancers, along with their English equivalent translations, are listed in .
The general search volume for all 3 urological cancers increased to a mean of 10,737.74 (SD 1026.29) from an initial mean of 5975.68 (SD 770.42). Specifically, the average daily search volume for bladder cancer rose to 3453.09 (SD 337.44) in 2023 from an initial average of 2275.72 (SD 302.17). For kidney cancer, the average daily search volume increased to 2976.78 (SD 319.64) from an initial average of 1706.84 (SD 262.95). Similarly, the search volume for prostate cancer grew to a mean of 4307.87 (SD 417.68) from 1993.12 (SD 297.99). According to the trend module, the total BSI for these top 3 urological cancers was 43,643,453. Specifically, the 13-year summed BSI ratio was 37.37% (15,972,271/43,643,453) for bladder cancer, 28.27% (12,079,106/43,643,453) for kidney cancer, and 34.36% (15,592,076/43,643,453) for prostate cancer (). Regarding topic preferences for each cancer, the BSI ratio for complaint and inquiry was dominant, accounting for 90.26%, 96.10%, and 79.53% across all 4 topics for bladder cancer, kidney cancer, and prostate cancer, respectively ().
To illustrate search trends over time since January 1, 2011, the daily request–based BSI for each cancer was analyzed both overall and by specific topics. The significance of these trends was evaluated using the APC model, as shown in and .
Based on the average annual BSI counts, a general growth in search requests for all 3 urological cancers was observed. The overall APC was 15.2% (P<.05) from 2011 to 2015, –2.8% from 2015 to 2021, and 8.9% from 2021 to 2023, resulting in an AAPC of 4.9%. For bladder cancer, the APC was 8.3% (P<.05) from 2011 to 2019, –11.7% from 2019 to 2021, and 7.4% from 2021 to 2023, with an AAPC of 2.8%. For kidney cancer, the APC was 8.0% (P<.05) from 2011 to 2019, –9.6% from 2019 to 2021, and 11.4% from 2021 to 2023, resulting in an AAPC of 3.9%. For prostate cancer, the APC was 17.7% (P<.05) from 2011 to 2015, –3.1% from 2015 to 2020, and 10.4% from 2021 to 2023, yielding an AAPC of 6.8% (P<.05).
Specifically within the bladder cancer theme, the APCs for the complaint topic were 8.0% (P<.05) from 2011 to 2021 and –5.1% from 2021 to 2023, with an AAPC of 1.2%. For the inquiry topic, the APCs were 20.8% (P<.05) from 2011 to 2014 and 1.2% from 2014 to 2023, with an AAPC of 4.8% (P<.05). For the prognosis topic, the APCs were –20.8% (P<.05) from 2011 to 2014, 15.6% from 2014 to 2018, and –6.9% from 2018 to 2023, resulting in an AAPC of –4.4%. For the treatment topic, the APCs were –5.4% from 2011 to 2016, 7.6% from 2016 to 2019, and –23.9% (P<.05) from 2019 to 2023, with an AAPC of –9.4%.
In the kidney cancer theme, the APCs for the complaint topic were 6.8% (P<.05) from 2011 to 2019 and –3.6% from 2019 to 2023, with an AAPC of 3.2% (P<.05). For the inquiry topic, the APCs were 14.0% (P<.05) from 2011 to 2017, –9.2% (P<.05) from 2017 to 2021, and 17.8% from 2021 to 2023, resulting in an AAPC of 6.2% (P<.05). For the prognosis topic, the APCs were –19.0% (P<.05) from 2011 to 2019 and 15.7% from 2019 to 2023, with an AAPC of –11.0% (P<.05). For the treatment topic, the APCs were 2.5% from 2011 to 2014, –47.1% from 2014 to 2018, and 42.6% from 2019 to 2023, with an AAPC of –12.2% (P<.05). In the prostate cancer theme, the APCs for the complaint topic were 25.4% (P<.05) from 2011 to 2013, 3.1% from 2013 to 2017, and –1.4% from 2017 to 2023, resulting in an AAPC of 4.2%. For the inquiry topic, the APCs were 21.2% (P<.05) from 2011 to 2015, –4.6% from 2015 to 2020, and 11.8% from 2020 to 2023, with an AAPC of 11.8%. For the prognosis topic, the APCs were –6.2% (P<.05) from 2011 to 2018 and 2.5% from 2018 to 2023, with an AAPC of –3.0% (P<.05). For the treatment topic, the APCs were 41.6% (P<.05) from 2011 to 2015, –5.8% from 2015 to 2018, and 17.4% (P<.05) from 2018 to 2023, resulting in an AAPC of 18.2% (P<.05).
Figure 1. Online search trends in bladder, kidney, and prostate cancer topics since 2011. (A) Searching trend of each cancer topic; (B) Sum BSI proportion of each cancer topic. APC: annual percentage change; BSI: Baidu Search Index. 
Figure 2. Online search trends for specific topics related to bladder, kidney, and prostate cancer since 2011. (A) Searching trend of specific topics in bladder cancer. (B) Sum BSI proportion of specific topics in bladder cancer. (C) Searching trend of specific topics in kidney cancer. (D) Sum BSI proportion of specific topics in kidney cancer. (E) Searching trend of specific topics in prostate cancer. (F) Sum BSI proportion of specific topics in prostate cancer. APC: annual percentage change; BSI: Baidu Search Index. Geographic DifferencesThe geographic distribution of each cancer type was calculated based on provincial BSI data and categorized according to the 7 Chinese administrative divisions []. shows the 13-year regional BSI proportions for each cancer type with valid search records. Search requests were predominantly from East China, accounting for 30.46%, 31.13%, and 30.47% of bladder, kidney, and prostate cancer searches, respectively, followed by North China. Search demand from Central China, South China, and West China was comparable, each contributing around 11%. The Northeast and Northwest regions ranked the lowest, collectively accounting for approximately 8% of searches for each urological cancer.
Figure 3. Regional distribution of online search in bladder, kidney, and prostate cancer topics. (A) Annual BSI trend for each region in the topic of bladder cancer. (B) Total search rates for each region on the topic of bladder cancer. (C) Annual BSI trend for each region in the topic of kidney cancer. (D) Total search rates for each region on the topic of kidney cancer. (E) Annual BSI trend for each region in the topic of prostate cancer. (F) Total search rates for each region on the topic of prostate cancer. BSI: Baidu Search Index. Demographic DifferencesFrom the demographic distribution analysis, variations in age and gender distribution were observed across each cancer theme and specific topic. In the bladder cancer theme, search requests for each topic were primarily made by individuals aged 20-29 and 30-39 years. For kidney cancer, the topics of complaint, inquiry, and prognosis were predominantly searched by the 20-29-year age group, whereas the topic of treatment was mainly searched by individuals aged 40-49 years. In the prostate cancer theme, the topics of inquiry and treatment were primarily requested by the 30-39-year age group, while searches for prognosis were mainly made by those aged 40-49 years. Notably, no dominant age group was identified for searches in the complaint topic for prostate cancer ().
Table 1. Demographic differences in each cancer topic.Theme and topic≤19 years20-29 years30-39 years40-49 years≥50 yearsFemaleMaleBladder cancerDuring the data-providing period from August 15, 2022, to August 13, 2023, 27,065 out of 31,200 words were identified as in-topic, representing valid user demand. The total BSI for these relevant user demand terms was 676,526,998, accounting for only 676,526,998 of 2,570,697,380 (15.74%) total search requests. Detailed distributions of these relevant terms and their search frequencies are shown in . The valid search ratio and demand distribution were also summarized overall () and specifically for each cancer theme ( and ). Additionally, the 3 most representative user-demand issues were identified and ranked based on frequency and search popularity ( and ).
Figure 4. erm categories related to all cancers (bladder, kidney, and prostate) in the Baidu Index user demand module (August 2022 to August 2023). (A) The most frequently appearing related words (word units) in Baidu Index searches related to bladder, kidney, and prostate cancers. (B) The most searched related words in Baidu Index inquiries related to bladder, kidney, and prostate cancers. BSI: Baidu Search Index; TCM: traditional Chinese medicine. 
Figure 5. Term categories of the most frequently appearing related words for each cancer (August 2022 to August 2023). (A) Most frequently appearing related words (word units) in Baidu Index searches related to (A) bladder cancer, (B) kidney cancer, and (C) prostate cancer. TCM: traditional Chinese medicine. 
Figure 6. Term categories related to the most searched related words for each cancer (August 2022 to August 2023).
Most searched related words (word units) in Baidu Index searches related to (A) bladder cancer, (B) kidney cancer, and (C) prostate cancer. BSI: Baidu Search Index; TCM: traditional Chinese medicine. Table 2. The top 3 most frequently appearing related words (word units) searched in the Baidu Index for each type of cancer.Category and termBladder cancerCount, nKidney cancerCount, nProstate cancerCount, nComplainaTCM: traditional Chinese medicine.
Table 3. The top 3 most searched related words in the Baidu Index for each type of cancer.Category and termsBladder cancerBaidu Search IndexRenal cancerBaidu Search IndexProstate cancerBaidu Search IndexComplain
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