According to The Oncologist medical journal, Less than 20% clinical trials are published in medical journals
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, you may recall, 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 percent, compared to 59 percent 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 - the outcome was disappointing or did not merit further consideration of the tested treatment, they report (look here).
Of course, we know why a registered trial may not be published - some fail and a researcher may decide the result doesn’t enhance knowledge or one’s reputation.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But “unpublished trials may have special importance in oncology, due to the toxicity and/or expense of many therapies,” they wrote.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?
Read full at pharmalot.com