Spin and bias occur in a high proportion of published studies of the outcomes and adverse events in phase III trials of breast cancer treatments, according to new research published online in Annals of Oncology.
Researchers at Princess Margaret Cancer Centre and the University of Toronto found that in a third of all trials that failed to show a statistically significant benefit for the treatment under investigation, the reports focused on other, less important outcomes to positively influence the interpretation of the results (Ann Oncol, January 9, 2013).
Contributing author Dr. Ian Tannock and colleagues identified all randomized, controlled, phase III trials for breast cancer therapies published between January 1995 and August 2011. Out of a total of 568 articles, 164 were eligible for inclusion in the analysis.
Trials always have a primary end point, a specific event measured at the end of the trial to determine whether or not the given treatment works. However, trials can also have secondary end points, or additional events that are of interest to the investigators but which the study is not specifically designed to address.
Tannock and colleagues found that 54 trials (33%) were reported as positive based on secondary end points -- despite not finding a statistically significant benefit for the primary end point. And in 110, or 67%, of the reports, there was bias in the way adverse effects of the treatment were reported, with more serious side effects (those with toxicities graded as III or IV) poorly noted, the team wrote.
The study did not find, however, that the source of funding for trials (either industry or academic) was associated with bias or spin in the reporting of results and toxicities, according to the team.
