Quality and accuracy of breast cancer information on the World Wide Web

Increasingly, patients are searching the World Wide Web for information about breast cancer. Most patients believe what they see online and many make treatment decisions based on this information. The purpose of our study was to evaluate the quality and accuracy of popular breast cancer-related Web sites. Methods: The top 200 sites returned in response to the query "breast cancer" by the search engine Google were evaluated for affiliation, medical information accuracy, and availability of four quality measures for health-related Web sites: authorship, date of update, references, and disclosure. We also documented whether each site displayed a seal from the Health on the Net (HON) Foundation, which is a nonprofit foundation with an 8-point code of conduct for Web sites providing medical information. Results: Of the 184 accessible Web sites, 36 were professional sites affiliated with universities, medical centers or government, 64 were affiliated with non-profit organizations, and 84 were commercial sites. Only 32 (17%) displayed the name, qualifications and affiliation of the author; 82 (45%) displayed the date of update, and 112 (61%) provided references. Disclosure of ownership, sponsorship, or conflicts of interest was found in 128 sites (70%). An HON seal was more likely to be displayed by commercial sites (25%) compared with professional sites (8%) and organizations (5%) (p=0.001). However, commercial sites were more likely to contain inaccurate medical information (13%) compared with professional (3%) and organization sites (0%) (p=0.004). Further, none of the sites that displayed the HON seal, actually met all 8 criteria required by HON. When sites were divided into low quality (met fewer than 3 of 4 quality criteria) and high quality (met 3 or more), low quality was significantly associated with inaccurate medical information (10% vs 2%, p=0.047). We found no inaccurate medical information in the 16 sites that met all four quality criteria. Conclusions: Voluntary quality standards such as HON are often not followed. Although patients believe the information that they see on the Web, there is reason to doubt its accuracy. Ensuring compliance with quality standards may increase medical information accuracy on the Web.