In NYC Subway, CyberKnife Prostate Cancer Ads Mislead

Survey Respondents Influenced by Claims

Nick Mulcahy

May 06, 2019

CHICAGO — Direct-to-consumer (DTC) advertising about the radiotherapy (RT) known as CyberKnife (CK), which is currently omnipresent in the New York City transit system, creates "inaccurate impressions" about the treatment's "comparative effectiveness and safety" in prostate cancer, according to new research.

That conclusion was made by investigators from Columbia University after they created on online survey involving 400 men that used language lifted directly from an advertisement. The investigators compared the participants' responses to the CK advertisement to responses to information about other prostate cancer treatments.

CK is a delivery system of high-dose RT to treat prostate cancer. However, there have been no high-quality studies that compared it with other RT methods, emphasized lead author Joseph Caputo, MD, a urologist at both Columbia University Irving Medical Center and New York–Presbyterian Hospital.

He discussed the study here during a press briefing at the American Urological Association (AUA) 2019 Annual Meeting.

"The CyberKnife ads are all over the subway, including at my Spring Street station in Soho. It's front and center," said Stacy Loeb, MD, a urologist at NYU Langone Health, New York City, who moderated the press event.

Notably, the New York ad campaign is sponsored by Winthrop Hospital in Mineola, New York, not by Accuray, makers of CK.

However, Caputo did not want to focus on the specific entity running the ads.

Although he and senior author Elias Hyams, MD, acknowledged that they were prompted to undertake the study after seeing the ads in the New York City subway system, Caputo said the bigger issue is DTC marketing, "which we believe should be discussed at the AUA meeting."

"This advertising tends to emphasize benefits over risks and offer unsubstantiated claims," he told reporters.

The new study is the first ever in urology to examine exposure to DTC ads and the related impact, said Loeb.

The text from the CK ad used in the survey reads: "CyberKnife is the biggest advance in prostate cancer treatment in a decade. CyberKnife is as effective as surgery for prostate cancer. But there's no cutting, no pain, no incontinence and less risk of impotence. Treatment takes just one week — five brief appointments."

In the new study, the investigators explored the question of whether or not exposure to this CK advertising affected perceptions of the technology compared with other treatments for prostate cancer.

To do so, they assigned the participating men to one of four arms: the CK ad; the same ad but with disclaimers that appeared in italics after the original claims; scientifically based information about other prostate cancer treatments; and a control ad that was not related to CK or prostate cancer. After viewing the initial ad, each man viewed the other ads as well.

Participants were then surveyed on risks and benefits of the CK and their likelihood of pursuing it vs other treatments.

The investigators report that the two arms who reviewed ads with CK claims were 40% to 45% more likely to select the technology as their preferred treatment. The effect was less pronounced in the group who received the scientifically based information (they were only 20 percentage points more likely to select the CK as the preferred treatment).

Notably, the scientific information–only group had more accurate impressions about CK's risks and benefits. Also, the CK advertisement group was the only group to consider CK superior regarding erectile and urinary preservation.

The addition of the disclaimer with the CK ad's assertions "mitigated positive impressions of erectile and urinary preservation, but participants were still more likely to believe CK is overall superior," say the study authors.

The authors and Loeb have disclosed no relevant financial relationships.

American Urological Association (AUA) 2019 Annual Meeting: Abstract 19-3138. Presented May 4, 2019.

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