Less than 20 percent of registered clinical trials of cancer drugs are eventually published in medical journals, according to a review published online by the The Oncologist medical journal.
A search of the National Institutes of Health’s ClinicalTrials.gov web site identified 2,028 registered research studies of cancer treatments. Major medical journals require all studies considered for publication be registered at ClinicalTrials.gov or another publicly accessible database.
And a subsequent search of the National Library of Medicine’s PubMed database showed that just 17.6 percent of the trials were eventually published in peer-reviewed medical journals.
The publication rate was particularly low for industry-sponsored studies, such as those funded by drugmakers (just 5.9% compared to 59% for studies sponsored by collaborative research networks. Of published studies, nearly two-thirds had positive results in that the treatment worked as hoped. The remaining one-third had negative results like the outcome was disappointing or did not merit further consideration of the tested treatment, they report.
The finding raises concern about publication bias in cancer treatment trials, according to the researchers, Scott Ramsey and John Scoggins of University of Washington and Fred Hutchinson Cancer Research Center in Seattle.
The researchers suspect the rate of negative results is much higher in the studies that have gone unpublished. “It is likely that many unpublished studies contain important information that could influence future research and present practice policy,” they wrote.
Of course, we know why a registered trial may not be published, some fail and a researcher may decide the result doesn’t enhance knowledge or one’s reputation. And some sponsors don’t want negative results out there. Same goes for some journal editors.
But “unpublished trials may have special importance in oncology, due to the toxicity and/or expense of many therapies,” they wrote. In other words, the knowledge base is incomplete. And who does that help?
Source: Pharmalot