The mental fog often experienced by breast cancer patients after chemotherapy might be due more to post-traumatic stress than to the cancer drugs, a new study suggests.
“Patients who complain of cognitive problems may actually suffer from post-traumatic stress or other substantial psychological consequences of having cancer, which can be treated,” Dr. Kerstin Hermelink from CCCLMU University Hospital of Munich, Germany.
“Physicians should therefore attentively listen to their patients who complain of cognitive impairment and try to understand their individual situation to find out what the patient needs,” she added.
The effects of chemotherapy on the brain have been blamed for the “brain fog” sometimes experienced by women with breast cancer, but similar symptoms have been reported by breast cancer patients who haven’t started their chemo yet and even by those whose treatment didn’t include chemotherapy, Hermelink and colleagues noted in the Journal of the National Cancer Institute.
To investigate, the researchers studied 150 women who had just been diagnosed with breast cancer, as well as 56 women without any health problems.
At several points during the following year, the women completed neuropsychological tests, as well as evaluations for post-traumatic stress disorder (PTSD). They also gave their own assessments of their cognitive function.
About seven months into the study (and about two months after completion of chemotherapy for the women who received it), there were no differences in cognitive performance or cognitive changes between women who received chemotherapy, women whose breast cancer was not treated with chemotherapy, and the healthy women without breast cancer.
At the end of one year, however, there was a small decline in the breast cancer patients compared to the healthy women, but the decline did not depend on chemotherapy treatment, according to the research team. Instead, it was linked with PTSD symptoms.
The U.S. Centers for Disease Control and Prevention defines PTSD as “an intense physical and emotional response to thoughts and reminders of the event that last for many weeks or months after the traumatic event.” Symptoms are varied and include – but are not limited to – flashbacks, nightmares, difficulty sleeping, being overly alert or easily startled, and having trouble concentrating.
“I personally was surprised how little cognitive change we observed,” Hermelink said. “All differences between the two patient groups and the control group were minimal, even though we used a large test battery and our study was comparatively well-powered, with a large sample.”
“Physicians should tell their patients that very subtle cognitive impairment is not only observed after chemotherapy but also in patients treated without chemotherapy, and even in patients who have not yet started any treatment for breast cancer at all,” she said. “The brain is not a machine that delivers the same level of performance as long as it is not broken but its function – and in the long run also its structure – are affected by our actions and experiences. The diagnosis of a life-threatening illness like breast cancer comes as a shock to most patients, which may leave traces in the brain, even if they cope very well.”
Hermelink added, “Research on cognitive impairment associated with cancer is full of methodological pitfalls that can substantially distort the results. It is almost impossible for people who do not work in the field to assess the methodological quality of a study and thus to find out whether or not the results are valid. Studies with spectacular findings are relatively easy to publish, even if they are small and their methods questionable, and of course, all researchers need to publish. Journalists and the public should therefore be particularly wary of small studies with large and unambiguous effects.”
By Will Boggs MD
SOURCE: Journal of the National Cancer Institute