Purpose: We aimed to assess the impact of spin (ie, reporting to convince readers that the beneficial effect of the experimental treatment is greater than shown by the results) on the interpretation of results of abstracts of randomized controlled trials (RCTs) in the field of cancer.
Methods: We performed a two-arm, parallel-group RCT. We selected a sample of published RCTs with statistically nonsignificant primary outcome and with spin in the abstract conclusion. Two versions of these abstracts were used-the original with spin and a rewritten version without spin. Participants were clinician corresponding authors of articles reporting RCTs, investigators of trials, and reviewers of French national grants. The primary outcome was clinicians' interpretation of the beneficial effect of the experimental treatment (0 to 10 scale). Participants were blinded to study hypothesis.
Results: Three hundred clinicians were randomly assigned using a Web-based system; 150 clinicians assessed an abstract with spin and 150 assessed an abstract without spin. For abstracts with spin, the experimental treatment was rated as being more beneficial (mean difference, 0.71; 95% CI, 0.07 to 1.35; P = .030), the trial was rated as being less rigorous (mean difference, -0.59; 95% CI, -1.13 to 0.05; P = .034), and clinicians were more interested in reading the full-text article (mean difference, 0.77; 95% CI, 0.08 to 1.47; P = .029). There was no statistically significant difference in the clinicians' rating of the importance of the study or the need to run another trial.
Conclusion: Spin in abstracts can have an impact on clinicians' interpretation of the trial results.
© 2014 by American Society of Clinical Oncology.