Engine failures: A critical analysis of current clinical trial websites' search engines.
Authors: Paunic Milica , Rim Claire , Hilal Olla , Nassar Renee , Zaib Farwa , Touma Kayla , Hossami Mahmoud , Abdel-Nabi Rhonda , Hirmiz Roaa , Hamm Caroline M. 
Published: June 2023

e18537 Background: Clinical trials are critical to treatment advancement as they provide a foundation for future discoveries. Currently, only 7% of cancer patients in Ontario are enrolled in a clinical trial and 1 in 4 clinical trials fails to recruit enough patients. Enrolling patients depends on finding suitable trials for them. Lack of trial availability is the most common barrier to trial recruitment especially in non-academic hospitals since they tend to hold fewer within-center trials compared to larger centers. Most must rely on finding trials via databases such as ClinicalTrials.gov, yet there is a lack of literature that critically examines these databases for their searching capabilities emphasizing the need for critical analysis of the current search engines for delivery of a suitable list of clinical trials for patients. Methods: From June to September 2022, three individuals were trained and hired to conduct searches for 18 cancer patients across five search engines through the Clinical Trials Navigator program. Upon receiving referrals, they each searched online repositories to find eligible trials for the patient. Each navigator conducted an initial search for each patient on ClinicalTrials.gov. In addition, each searched alternative websites: Navigator 1 searched CanadianCancerTrials, Navigator 2 searched ClinicalTrialsOntario, and Navigator 3 searched Canadian Cancer Clinical Trials Network and OncoQuebec. For every search, each tracked search key words, total trials shown, total eligible trials found, and the number of eligible trials found on alternate websites that were not present in the initial ClinicalTrials.gov search. A qualitative analysis was done in tandem to identify shortcomings in the search engines. All searches were amalgamated by the lead navigator. Results: Our findings reveal pitfalls in the clinical trial search system, such as dysfunctional search filters, inconsistent results across the different websites, outdated trial information, and most importantly, lack of reproducibility as well as a lack of thoroughness of search results. On ClinicalTrials.gov, out of 54 search results, only 6 were reproducible between navigators. The only searches that were consistent between the navigators revealed zero trials for the patient. Not only was there variability in the total number of studies shown per same patient search by different navigators despite using similar or identical search terms, but there was also variability in the total number of eligible studies for the patient. Conclusions: The functionality of clinical trials search engines compromises equitable access to clinical trials, and impair clinical trials accrual. The highlighted challenges of the current clinical trials search engines available to patients and health care professions indicate an inefficient process that may be compromising clinical trial recruitment and thus potential patient outcomes.