YouTube videos about prostate cancer are putting patients at risk of harm because of misleading medical information, a team of researchers has claimed.
Scientists from the NYU School of Medicine analysed the 150 most-viewed YouTube videos on the disease and reported that 77% had factual errors or biased content in either the video or the comments section.
Their work, published in the journal European Urology, found that while 75% of the videos fully described the benefits of different treatments, only 53% warned of their side effects.
According to the team, 19% of the videos also recommended alternative and unproven medicines – some of which could directly harm patients.
One video promoted "injecting herbs" into the prostate to treat cancer.
The researchers said the audiences for these videos was large, with the highest total viewership at 1.3 million.
"Our study shows that people really need to be wary of many YouTube videos on prostate cancer," said urologist Dr Stacy Loeb, who chairs a panel of social media experts for the American Urological Association (AUA).
"There is valuable information available in them, but people need to check the source to make sure it's credible and to beware of how quickly videos become outdated as care guidelines constantly evolve with the science."
Dr Loeb said that credible online sources for information about prostate cancer are widely available. In the UK, the website for the NHS offers details about diagnosis and treatment.
She added that the volume of videos on YouTube makes it impractical for medical experts to continually review them all as part of any "policing" effort.
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However, she suggested that doctors and viewers should use YouTube's reporting feature to alert the tech giant to videos that promote misleading information.
A spokesperson for YouTube was unable to immediately respond to Sky News when contacted.