Healthy Skepticism Library item: 14613

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Publication type: Journal Article

Ramsey S, Scoggins J.
Commentary: Practicing on the Tip of an Information Iceberg Evidence of Underpublication of Registered Clinical Trials in Oncology
The Oncologist 2008; 13:925–929
http://www.theoncologist.com/cgi/reprint/theoncologist.2008-0133v1.pdf

Abstract:

Objective. Members of the International Committee of
Medical Journal Editors require, as a condition of consideration
for publication, that all clinical trials be registered
in a public trials registry. We evaluated the
proportion of registered trials that are published in the
peer-reviewed literature.
Methods. After downloading the contents of the National
Institutes of Health’s ClinicalTrials.gov registry,
we used key words to identify trials in oncology. We
then evaluated the proportion of trials that had been
published in journals listed in PubMed.gov. Among trials
with published results, we determined the proportion
that reported positive versus negative results.
Results. Among the 2,028 trials meeting the inclusion
criteria, 17.6% were available in PubMed. Twenty-one
percent of the trials registered before September 1, 2004
were published, compared with 11.9% of those registered
after this date. Trials sponsored by clinical trial
networks published the greatest proportion of registered
studies (59.0%); studies sponsored by industry
published the fewest (5.9%). Among published studies,
64.5% reported the results as positive findings.
Conclusions. Less than one in five studies in cancer
that are registered with clinicaltrials.gov have been
published in peer-reviewed journals. Research sponsors,
researchers, and journal editors should redouble
their efforts to encourage publication of registered clinical
trials in oncology.

Keywords:
Cancer • Clinical trials • Registries • Publication bias