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The Conversation
The Conversation
Alessandro Marcon, Senior Research Associate at the Health Law Institute, University of Alberta

Google searches for information about cancer lead to targeted ads from alternative clinics

Online searches for health information can pull up misleading ads. (S. Ghassimi), CC BY

More than 80 per cent of online searches are now performed with Google. But there’s an insidious element to the world’s most popular search engine. As companies compete for the advertising spaces that accompany search query results, users seeking critical health information can be exposed to dangerous and exploitative misinformation.


Read more: Why we fall for fake health information – and how it spreads faster than facts


In 2024, North Americans overwhelmingly used Google for news and information on politics, celebrities, entertainment and topical events like natural disasters. Health-related queries are also popular: nearly 70 per cent of the Canadian public use online searches for health information.

a hand holding a smartphone showing Google search
Google is the world’s most popular search engine. (Shutterstock)

Online searches

The phrases or questions contained in online searches serve as valuable data. They can inform epidemiological surveillance and provide insight into popular global and regional trends.

These data also hold immense value for online marketing teams, tracking who is searching for what, where and when. In addition to search tracking, however, queries now are used for online advertising. It’s a reality that raises serious ethical, regulatory and public health issues.

Before the internet, key advertising spaces existed in magazines and newspapers, on highway billboards and time slots between radio and television programming. Advertising is so lucrative that a 30-second time slot during the Super Bowl now costs upwards of US$8 million.

Online, fixed slots have now been replaced by targeted advertisements to accompany search results, determined by search queries entered by users.

Highly coveted spots

Like a Super Bowl ad, advertising on Google’s first page results is highly coveted.

Obtaining the rights to these space requires companies to outbid one another to win the ads spaces determined by search terms — an advertiser can purchase ad space from Google associated with a specific phrase or keyword.

Companies with snack products, for example, may compete for their sponsored content to appear when individuals search for “Super Bowl party snacks,” “new chip flavours” or “chip and dip ideas.”

As harmless and obvious — and perhaps even inevitable — as this marketing approach may seem, the practice is problematic when industry targets personal, sensitive and critical health terms — which is exactly what our research uncovered.

Searches for cancer, exploitative ads

Using the AI-driven marketing platform SemRush, we analyzed the search terms purchased for advertising by notorious alternative cancer clinics in Tijuana, Mexico and Arizona. We determined what queries were targeted and how much was spent on acquiring the advertising space matching these queries.

We also assessed whether this spending increased traffic to their clinic websites. Our results showed that over roughly one decade, these clinics paid over an estimated US$15 million to purchase the ad spaces for thousands of search words and phrases.

These search queries related to cancer prognosis and diagnosis, treatment options including alternative treatments and cancer types including late-stage cancer. In sum, the advertising strategy generated more than 6.5 million website visits for alternative cancer clinics.

a person lying down with their head and shoulders covered by a white netting
Alternative cancer treatments can interfere with the success of medical treatments. (Shutterstock)

Negative health impacts

Unfortunately, the success of these alternative clinics’ marketing strategies is nothing short of a disaster for the public’s health and well-being. Alternative cancer treatments are associated with an increased risk of death and offer false hope for those suffering from end-stage cancer.

These ineffective and oftentimes dangerous treatments can financially exploit patients, disrupt end-of-life planning and interfere with evidence-based cancer or palliative treatments.

Google is therefore enabling an advertising option that contributes to the harmful spread of inaccurate and damaging cancer misinformation that can directly lead to detrimental health-related actions.

Protection from deception

Our research focused entirely on the cancer context and analyzed the targeted search query approach of problematic clinics in two specific locations. It is imaginable — indeed very probable — that this approach is deployed in other health contexts and beyond.

Google does have and enforce policies to protect users from deceptive advertising content. But there is little oversight regarding how advertisers may exploit its keyword ad matching features.

It’s imperative that Google take action to restrict its ads mechanism from being used in this exploitative manner. Search results could give prominence only to websites supported by accurate scientific evidence. Google could prohibit the advertising purchase of ostensibly controversial search terms. This would include personal, sensitive queries from vulnerable groups, including patients suffering from cancer and other life-threatening ailments.

Google and other social media platforms benefit financially from misinformation. It is up to these companies to decide if human health and well-being is more valuable than these financial gains. It is up to all of us to advocate for those harmed by dangerous misinformation.

The Conversation

Alessandro Marcon works at the University of Alberta's Health Law Institute, which has received funding related to this project from CIHR.

Marco Zenone is the recipient of the Banting Postdoctoral Fellowship from the Canadian Institutes of Health Research.

This article was originally published on The Conversation. Read the original article.

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