Monday, April 22, 2013
Historically, a frustration among researchers has been that neuropsychological testing is not sensitive enough to confirm a patient’s complaints of memory issues after chemotherapy. Imagine then how patients feel. They may have already submitted to batteries of testing. And that testing may not have matched self-reports of memory loss, or struggles attending to the tasks of everyday life, or issues with word retrieval.
Brain scans, on the other hand, can successfully detect cognitive impairment after treatment. My co-author, Dan Silverman, and his UCLA team, were among the first scientists to use PET scans to link impaired brain function with chemotherapy and hormonal therapies. Those results were published back in 2006. Other researchers have noted changes in brain structure after chemotherapy through studies with MRI.
But not everyone has access to a brain scan or cares to submit to one. A sit-down interview with a neuropsychologist and a fill-in-the-dots paper-and-pencil test is far more palatable to many patients.
In this current UCLA study, published this week in the Journal of the National Cancer Institute, researchers investigated whether neuropsychological testing would validate a patient’s report of problems with thinking and memory in a consistent way. Patti Ganz, MD, headed the study and Dan Silverman is a co-author.
To answer the question, the team enrolled 189 newly diagnosed breast cancer patients (stages 0, 1, 2, or 3A) in the study. Timing was important. As other research has shown a link between anti-estrogen drugs (tamoxifen, aromatase inhibitors) and memory deficits, Ganz and colleagues wanted to make sure the women had completed primary cancer treatment but had not yet begun endocrine or hormonal therapy. Women with serious anxiety and depression were excluded from the study as these symptoms also can cloud memory.
Participants completed a questionnaire asking about their cognitive symptoms and went through a battery of neuropsychological tests. When compared, the researchers found a direct correlation between a high level of patient complaints and low test scores. Regarding memory, 23% of patients had higher complaints than those in a control group and 19% reported higher complaints about executive functioning (problem solving, reasoning, etc.). Researchers also found a correlation between low test scores, combined chemotherapy and radiation treatments, and symptoms of depression.
This study is by no means the first to find a scientific basis for a patient’s cognitive complaints. In fact, the literature on this dates back to the 1990s. Other scientists as well have looked at patient self-reports and whether those reports mesh with quantifiable chemo brain. The UCLA study builds on that work.
According to Dr. Ganz, “In the past, many researchers said that we can’t rely on patients’ self-reported complaints or that they are just depressed because previous studies could not find this association between neuropsychological testing and cognitive complaints. In this study, we were able to look at specific components of the cognitive complaints and found they were associated with relevant neuropsychological function test abnormalities."
In other words, the UCLA study further refines the literature backing us up as patients, confirming that as a group, we are not imagining our symptoms. And that’s a good thing, but at some point we need to stop proving the obvious. This phenomenon we call, “chemo brain,” is already known and accepted by the scientific community.
As Christina A. Meyers, Ph.D., Chief of Neuropsychology (retired) at M.D. Anderson Cancer Center says in her accompanying editorial, it’s time to move forward. Let's get to the interventions.