In the United States, skin cancer is the most common cancer affecting both men and women, and incidence rates have recently been rising [1,2]. Early detection and treatment influences mortality risk, particularly with melanoma [3]. Public understanding about the causes, consequences, and treatment of skin cancer may influence individuals’ motivation and ability to make informed decisions regarding prevention, early detection, and treatment. The public has increasingly used the Internet in general and social media in particular as a source of information [4].

YouTube is a popular social media website with approximately one billion unique worldwide users per month [5]. With this extent of reach, there is great potential for both improving understanding or, conversely, creating confusion and disseminating inaccurate and potentially dangerous information. There is limited research on the content of YouTube videos related to public health. In this study, we assessed selected aspects of the most widely viewed YouTube videos related to skin cancer.

Using the keywords “skin cancer”, all videos in English were sorted by number of views. Those with 5000 or more views were included in the sample. Each video was classified as being posted from a professional source or consumer. Professional videos were defined as those derived from a health or non-profit organization, or featuring one or more professionals with clinical credentials. Consumer videos featured people with no clinical credentials and the originator was not affiliated with any organization.

A total of 140 professional and consumer videos uploaded between 2007 and 2014 were identified and coded by 1 researcher (RR); 10 were re-coded by 2 researchers (CHB and RR) to demonstrate that the coding was completed in a consistent way. Coding involved an identifying and sorting process followed by gathering descriptive information, including length of the video, number of views, and year uploaded. A dichotomous coding scheme (ie, yes or no) was used in coding specific aspects of video content, including provision of information, type of skin cancer, age group, family history, risk reduction, risk factors, fear, and home remedies for skin cancer treatment.

Descriptive statistics, including frequencies, percentages, means, and standard deviations, were calculated to describe the year each video was uploaded, number of views (since the date of upload), duration (in minutes), and number of views. Chi-square analysis for categorical variables and Student’s t test for continuous variables were used to assess if there were differences between videos posted by consumers versus professionals concerning characteristics and content. Interrater reliability was assessed using Cohen’s kappa and was found to be excellent (kappa=.99). P values <.05 were considered statistically significant. All analyses were performed using IBM SPSS (version 22).

Collectively, the 140 videos were viewed more than 33 million times (range 5131-9,049,986 views) (Table 1). Consumers created the majority of videos (60.0%; 84/140). The mean length of the videos was 5 minutes (range: 28 seconds to 86 minutes). There were no statistically significant differences between videos posted by consumers versus professionals with respect to number of videos represented, length, or number of views. There were, however, differences in other respects.

The majority of videos (61.4%, 86/140) provided information related to skin cancer screening and tended to discuss skin cancer in general (32.1%, 45/140) or melanoma (26.4%, 37/140) (Table 2). Overall, content was not directed at any specific age group (88.6%, 124/140). Risk reduction was commonly discussed covering signs and symptoms of skin cancer (32.9%, 46/140), importance of screening (28.6%, 40/140), use of sun block (27.9%, 39/140), and dangers of tanning (27.1%, 38/140). Compared with consumer-created videos, those created by professionals more often provided information (P<.001), mentioned squamous cell skin cancer (P=.02), focused on importance of screening (P<.001), and on signs and symptoms (P<.001). These videos were also more likely to discuss the ABCDE method of skin cancer self-examination (P=.026). Videos created by consumers conveyed information related to the use of black salve as a home remedy cure of skin cancer (consumer 27.7%, 23/83 vs professional 0.0%, 0/57, P<.001) (Figure 1-3).