Researchers at the University of Michigan Comprehensive Cancer Center have found a strange pattern in the almost one-third of cancer studies that are published in reputed science journals - they do not disclose their correct sources of funding, the authors, and report only positive findings.
The researchers say that the most frequent type of conflict was industry funding of the study, which was seen in 17 percent of papers.
In about 12 per cent of the papers, they said, the authors of the studies were found to be industry employees.
Randomised trials, on the other hand, were more likely to have positive findings, said the researchers.
"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. It's becoming increasingly clear that we need to look more at how we can disentangle cancer research from industry ties," said study author Dr. Reshma Jagsi, assistant professor of radiation oncology at the U-M Medical School.
The researches analysed 1,534 cancer research studies published in prominent journals.
"A serious concern is individuals with conflicts of interest will either consciously or unconsciously be biased in their analyses. 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," said Jagsi.
And, for example, she said that researchers might design industry-funded studies in a way that's more likely to produce favourable 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. 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 endeavour 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," said Jagsi.
The results of the current study appear online in the journal Cancer.