While it's a good thing that the conflicts were disclosed, the review also found conflicts affect the research outcomes. The results, announced today, will be published June 15 in the journal Cancer.
The findings add to a mountain of evidence suggesting you should be skeptical of health and medical advice.
Other investigations have indicated that many medical studies simply are not accurate. Further, the media is known to distort key aspects of medical studies, twisting findings by virtue of ignorance, blowing obscure, unpublished "breakthroughs" out of proportion, and frequently failing to disclose industry funding even when the researchers do mention it.
Even common existing treatments can be found pointless, as in 2007 when researchers showed that honey works better than cough medicines in soothing children's coughs.
Drugs are, of course, big business. So there is incentive to fund studies that will shine positive light on a drug. Other industries do the same. A recent study funded by gum-maker Wrigley found — no surprise — that chewing lots of its sugarfree gum can help you cut down on calories.
The most frequent type of conflict revealed by the new review was industry funding of the study, found in 17 percent of papers. In another 12 percent, at least one of the study authors was employed by the industry — drug companies and others aiming to market treatments to patients.
Drug trials with reported conflicts of interest were more likely to have positive findings, the review revealed.
"Given the frequency we observed for conflicts of interest and the fact that conflicts were associated with study outcomes, I would suggest that merely disclosing conflicts is probably not enough," said study author Dr. Reshma Jagsi, an assistant professor of radiation oncology at the University of Michigan Medical School. "It's becoming increasingly clear that we need to look more at how we can disentangle cancer research from industry ties."
Many of the studies are likely wrong anyway, other research indicates.
Medical scholar John Ioannidis of the Ioannina School of Medicine in Greece and Tufts University in Medford, Mass. has analyzed medical studies over the years and concludes that most are flawed by poor study design, bad math or self-serving data analysis. Other researchers have countered, however, that multiple studies of a given treatment tend to clearly bear findings out or refute them over time.
Conflict affects outcome
In the new study, Jagsi and her colleagues found other dubious outcomes. They looked at 1,534 cancer research studies published in prominent journals.
Studies that had industry funding focused on treatment 62 percent of the time, compared to 36 percent for other studies not funded by industry. And the studies funded by industry focus on epidemiology, prevention, risk factors, screening or diagnostic methods only 20 percent of the time, vs. 47 percent for studies that had declared no industry funding.
"A serious concern is individuals with conflicts of interest will either consciously or unconsciously be biased in their analyses," Jagsi said. "As researchers, we have an obligation to treat the data objectively and in an unbiased fashion. There may be some relationships that compromise a researcher's ability to do that."
For example, she said in a statement, researchers might design industry-funded studies in a way that's more likely to produce favorable results. They might also be more likely to publish positive outcomes than negative outcomes.
"In light of these findings, we as a society may wish to rethink how we want our research efforts to be funded and directed," Jagsi said. "It has been very hard to secure research funding, especially in recent years, so it's been only natural for researchers to turn to industry. If we wish to minimize the potential for bias, we need to increase other sources of support. Medical research is ultimately a common endeavor that benefits all of society, so it seems only appropriate that we should be funding it through general revenues rather than expecting the market to provide."
Jagsi and her colleagues looked at all original clinical cancer research published in five top oncology journals and three top general medical journals in 2006, including the New England Journal of Medicine, the Journal of the American Medical Association, Lancet, and the Journal of the National Cancer Institute.
Media gets it wrong, too
There are other reasons for the average person to be skeptical about medical breakthroughs.
Peer-reviewed journals act as filters, with findings reviewed by capable colleagues before publication. Plenty of medical research that has yet to be published makes it into the popular media, too, where more distortions take place.
A study in 2006 found that out of 175 stories in the popular media that discussed unpublished research, only two noted that the research was unpublished.
But even if a study is published in a peer-reviewed journal, that doesn't mean the media will do its job. A 2008 study detailed in JAMA looked at 306 news articles, online and in newspapers, that dealt with about company-funded medication studies. Only 42 percent of the articles disclosed the fact that industry had funded the studies.
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Robert Roy Britt is the Editorial Director of Imaginova. In this column, The Water Cooler, he looks at what people are talking about in the world of science and beyond.