- Design
- Two online randomised trials
- Population
- 6,272 census-matched US adults
- Primary outcome
- Change in hypothetical decision to take a new cancer drug
- Effect
- −10.1 percentage points (95% CI −11.7 to −8.5) with one uncertainty disclosed
JAMA Internal Medicine reported two online randomised trials in 6,272 US adults, census-matched, who were asked whether they would take a hypothetical new cancer drug. Participants were shown plain-language statements about common gaps in the evidence: a single-arm trial, a short study, a surrogate endpoint, an unrepresentative population, or no evidence that patients would notice an improvement.
Learning about any one uncertainty reduced willingness to take the drug by 10.1 percentage points on average, and by 14.1 points when told patients might not notice an improvement. Each additional uncertainty reduced it further. Perceived effectiveness and trust fell; worry did not change.
Many cancer drugs reach patients on accelerated or surrogate-based approval. Internists often help patients with multimorbidity weigh these choices. These findings suggest the uncertainties matter to patients when they are told about them.
The decisions were hypothetical and online; real patients facing cancer may weigh things differently.
- Tell patients when a drug's approval rests on a surrogate endpoint or a single-arm trial
- Say plainly when it is unknown whether patients feel better on the drug
- Expect some patients to decline once they understand the uncertainty, and respect that choice
- Raise these points especially for patients with multimorbidity, where benefit is least certain
Why it matters
Informed consent for new drugs is incomplete if the uncertainty is left out.
Don't overread it
These were hypothetical choices by online participants, not decisions by patients with cancer.
The statistics, in plain English
A 10.1-point drop (95% CI 8.5 to 11.7) means about one in ten participants changed their answer after one sentence of information.
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