Multi-cancer Early Detection and Other Tests: Misleading Social Media Posts

Although social media makes health information easier to access, it also enables false or incomplete information to spread. A study published on February 26, 2025, in JAMA Network Open found misleading posts on Instagram and TikTok about multi-cancer early detection (MCED) tests and other medical tests. Most posts were shared by influencers, and much of the content was promotional.

Social Media as a Source of Medical Misinformation

This poses a serious threat to healthcare systems and shows how social media has become a dumping ground for medical misinformation. False or deliberately incomplete information can create a public health crisis.

The study examined 982 Instagram and TikTok posts shared between April 30, 2015, and January 23, 2024. The accounts had a combined 194.2 million followers. Only 16% of posts (n=156) came from users identifying themselves as doctors.

Posts About MCED Tests

Multi-cancer early detection (MCED) tests are a new generation of screening tests intended to identify several cancers before symptoms occur using circulating genetic markers and biomarkers. In theory, detecting cancer earlier aims to improve treatment prospects. However, these tests have not yet received United States Food and Drug Administration (FDA) approval for general use and are available only in limited commercial settings. Research into accuracy, false positives, and clinical benefit is ongoing, and experts urge caution about overdiagnosis that may lead to unnecessary interventions.

The JAMA study found that 87% of posts (n=855) emphasized potential benefits, whereas only 15% (n=144) mentioned potential harms. Another 5% (n=46) downplayed harms, and 6% (n=60) mentioned overdiagnosis. Only 6% of posts (n=63) referred to scientific evidence.

Among 197 MCED-related posts, 99% (n=195) discussed benefits and 31% (n=60) mentioned harms. However, 20% (n=39) downplayed harms, and only 3% (n=5) mentioned overdiagnosis.

In addition, 94% of MCED posts (n=186) were promotional, only 5% (n=10) drew on scientific evidence , and 22% (n=44) included personal anecdotes. Influencer financial interests were disclosed in 45% (n=89), while 38% (n=75) recommended that followers undergo testing.

Misleading Information and a Lack of Scientific Evidence

Dr. Brooke Nickel of the University of Sydney said influencers were marketing these tests under the guise of early screening. "These tests are unnecessary for most people, and evidence for the effectiveness of some is inadequate. Much of the content shared under the message 'knowledge is power' consists of cherry-picked information . Seeing the whole picture is essential in healthcare, and half-truths often lead to misinformation."

The study also found that, compared with other influencers, the likelihood of doctors' posts mentioning the tests' potential harms was 4.49 times higher (OR: 4.49; 95% CI: 2.85-7.06). They were also 2 times more likely not to be promotional (OR: 0.53; 95% CI: 0.35-0.80).

Evidence-based posts were 51% less likely to mention benefits (OR: 0.49; 95% CI: 0.26-0.92) and 11.65 times more likely to emphasize harms (OR: 11.65; 95% CI: 6.77-20.08).

Influencers with financial interests were 76% less likely to mention harms (OR: 0.24; 95% CI: 0.17-0.35) and 87% less likely to mention overdiagnosis (OR: 0.13; 95% CI: 0.06-0.30).

Conclusion: Stronger Social Media Oversight Is Needed

Instagram and similar platforms are taking an increasingly relaxed approach to checking medical information. This allows misleading content threatening public health to spread rapidly. More effective regulation and oversight are therefore becoming essential to prevent medical misinformation and protect the public.

Alongside platforms and authorities, we also have a major responsibility as individuals. Readers should question the information they encounter and seek scientific evidence.

Reliable information sources:

• present both the advantages and disadvantages of a study transparently,
• clearly cite scientific data, and
• present expert views objectively.

Comparing influencers' or commercially interested individuals' statements against scientific sources and verifying them is part of individual responsibility. Protecting our health means making decisions based on complete, clearly presented scientific information.

Instagram and similar platforms are taking an increasingly relaxed approach to checking medical information. This allows misleading content threatening public health to spread rapidly. More effective regulation and oversight are therefore becoming essential to prevent medical misinformation and protect the public.

Platforms such as Instagram are moving away from checking information in posts. Stronger regulation is therefore needed to prevent misleading medical information from spreading.