Poor people are less likely to take part in clinical trials for new cancer drugs, which can make it harder to develop treatments, according to a new study.
"Cancer clinical trials are how we move the field forward. As a result of patients not participating in clinical trials, it takes a lot longer and it's much more expensive to develop new therapies," said Dr Dawn Hershman, who worked on the study.
"In this study we found one factor that contributes to that is patient income," said Dr Hershman, from Columbia University in New York.
Another reason to be worried about people not participating, according to the researchers, is that an underrepresentation of one group in a clinical trial may mean that the findings aren't applicable to the general population.
"We need to make sure that we make accommodations so that people in the trials reflect those who are in the general population and those who will be taking the drugs," said Dr. Jean Ford, who was not involved with the new study but has researched barriers to clinical trial participation.
How the study was done
Between 2007 and 2011, the researchers surveyed nearly 5 500 people who were recently diagnosed with breast, colorectal, lung or prostate cancer.
The online survey asked whether or not the patients were invited to take part in a clinical trial and if they joined. It also collected demographic information.
Overall, 2 174 patients said they talked about clinical trials with their doctors. About 45% were invited to join a trial, and about half said yes.
Ultimately, 9% of the original group took part in a trial.
What the study found
The researchers then looked at which patients were most likely to say yes. They found 10% of patients making $50 000 or more per year enrolled in a trial, compared to 7.6% of those making less than that.
Even in a multivariable model adjusted for comorbidities, "income remained a statistically significant predictor of clinical trial participation," the authors said.
Dr Hershman and her colleagues found that the difference in participation based on income also applied to patients 65 years old and older, who don't normally worry about costs because they qualify for Medicare.
That suggests, the researchers said in the Journal of Clinical Oncology, that the difference between poor and wealthy individuals goes beyond access to care.
There could be several reasons why poor patients are less likely to take part in clinical trials. For example, the researchers found doctors were less likely to offer them a spot in a trial - if one was discussed at all.
Also, they found low-income patients were more likely to be concerned about the costs associated with clinical trial treatments, compared to wealthier patients.
Those concerns, said Dr Hershman, can go beyond paying for the treatment to patients being worried about gas money and taking time off work.
"There are numerous barriers, but where we are lacking is in developing interventions that actually work to recruit some of the groups that are underrepresented," said Dr Ford, the chair of the department of medicine at The Brooklyn Hospital Center.
"The bottom line is that if we are going to bring such populations into trials we are going to have to invest in the infrastructure to make it happen," said Dr Ford.
(Reuters Health, January 2013)
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