Previous studies of cancer survivors who display symptoms of chemobrain showed they sometimes performed poorly on memory tests, but did not explain why.
The BCRT study administered short-term memory tests to 21 women who had breast cancer surgery -- 16 of whom had chemotherapy treatments from five to 10 years earlier -- and then took a picture of their brains using a PET scanner. The pictures showed the frontal cortex -- which is associated with memory -- of the women with chemobrain symptoms had changed the way it normally functioned, and had to work harder to remember information on the memory tests. The women who did not undergo chemotherapy treatments showed no sign of any change in brain function.
According to lead researcher Daniel Silverman of the University of Callifornia, Los Angeles, chemotherapy was originally only administered to breast cancer patients when the disease had spread to other parts of the body, but lately it has been used increasingly to lower the risk of reoccurrence after surgery. He said the approach can save lives, but produces more survivors with chemobrain.
UCLA cancer specialist Patricia Ganz said that cancer patients should not balk at chemotherapy because they are afraid of developing chemobrain, adding that not every patient will experience these symptoms. Ganz also noted that the BCRT study was too small to prove that chemotherapy actually causes forgetfulness, and that depression has also been known to cause mild memory loss.
However, previous studies suggest anywhere from 25 percent to 82 percent of breast cancer survivors suffer from chemobrain. Silverman said the studies tend to revolve around breast cancer patients because they have a high survival rate after chemotherapy, but said that chemobrain may also affect other cancer survivors.
Ellen Coleman, associate executive director of the non-profit group CancerCare, agreed. She noted that many of the 10 million cancer survivors in the United States have undergone chemotherapy treatment.
Mike Adams, natural health advocate and outspoken critic of conventional cancer treatment, said that the study has illustrated just one more harmful side effect of chemotherapy.
"That brain-damaging chemotherapy is still practiced in modern medicine is perhaps one of the clearest examples of the egregious failure of medical science to actually help people heal," he said.