(Reuters Health) – Cancer drugs that prevent tumors from growing may not lead to a better quality of life for patients, a new study suggests.
"In countries where patients have to pay co-pays, they can use up all of their savings to access those expensive new drugs and eventually they can not prolong their lives or improve the quality of their lives," Feng Xie, a professor in the health economics at McMaster University, Reuters Health said.
Xie and colleagues have re-analyzed data from nearly 40 randomized trials with multiple cancer types. They found that & # 39; progression-free survival & # 39 ;, or the time that doctors could control the cancer was not related to health-related quality of life.
Today, cancer researchers and drug companies often use progression-free survival as a measure of the effectiveness of a new drug, Xie explained by telephone.
"In the past, when a new drug was developed, overall survival – that is, how long the patient lived – was" the end point to evaluate. "Many medications have now been approved based on the benefit of progression-free survival," Xie said.
One reason for using progression-free survival as an indicator of effectiveness is that it can be measured faster than overall survival, so that new drugs can get through the pipeline faster, says Xie and colleagues in JAMA's internal medicine. .
The problem, said Xie, is that progression-free survival, measured in the short term, does not necessarily predict a longer life span. And as the new study shows, it can also predict a poor quality of life.
"In cancer patients, there are two important things in evaluating a therapy: whether it prolongs survival and improves quality of life (even if it does not prolong survival)," explained Xie.
Although many studies have measured progression-free survival, most have not reported on health-related quality of life. Xie and his colleagues were able to find 38 studies, including a total of 13,979 cancer patients with 12 different cancer types, who looked at both endpoints.
Data collected from all 38 studies showed no significant association between progression-free survival and quality of life.
The researchers had difficulty comparing data from the studies, because quality of life was not always measured in the same way. Xie hopes that researchers will standardize the way in which they measure the quality of life in the future.
Dr. Robert Ferris, director of the Hillman Cancer Center at the University of Pittsburgh Medical Center, is not ready to stake out progression-free survival as an indicator of the effectiveness of a cancer drug. But the early marker may underestimate or overestimate the value of a drug, Ferris said in a telephone interview.
"Early response does not always predict survival in the long term," said Ferris, who is not affiliated with the new study. "Medicines for immunotherapy, for example, are known for their long-term benefits, but may not have the early rapid shrinkage of a tumor."
Also, said Ferris, measuring the quality of life can be difficult. "Everyone sees it differently," he explained. "Some may see it as a reduction in pain, others may see it as the ability to communicate socially or the ability to swallow or the ability to get out of bed, others may see it as a reduction in fatigue."
Still, progression-free survival can be used as an early indicator that researchers are on the right track with a new drug, Ferris said. When an experimental medicine, for example, can properly control a tumor, this can give researchers the impetus to carry out tests on a larger scale.
"You have to be judicious about how you use it," concluded Ferris.
SOURCE: bit.ly/2QoLsZv JAMA Internal medicine, online 1 October 2018.