Randomized placebo-controlled clinical trials are the gold standard for demonstrating the efficacy and toxicity of new treatments and drugs, but according to a new study, most of them are compromised by poor or biased reporting of benefits and harms.
Researchers examined 164 trials of treatments for breast cancer published from 1995 to 2011, including studies of chemotherapy, radiation and surgery. The Annals of Oncology posted their results online last week.
Almost a third of the trials reported a positive result that was not based on the primary goal of the study, but rather on a secondary one more likely to be due to chance. And two-thirds of the trials failed to accurately report the toxicity of the intervention under study, the researchers found.
The authors used a seven-point scale to report the way side effects were described, depending on whether they appeared in the abstract, were discussed in the conclusions, or were frankly acknowledged in other ways. They found that the more effective a treatment was said to be, the more likely the bad side effects were minimized.
“Reports of studies need to be looked at quite critically,” said the senior author, Dr. Ian F. Tannock, a professor of medical oncology at the University of Toronto. “Many of them are using spin and bias to make the results look more impressive than they really are. And that can have implications for the choice of treatment for individual patients.”