Cognitive impairment occurs in 25% of patients with breast cancer

In In The News by Barbara Jacoby

By: Janet Miller


About one of four patients with breast cancer experienced cognitive impairment, and it was “not exclusively related” to the patient’s therapy, researchers wrote in Psycho-Oncology.

“As clinicians, we encounter many patients with breast cancer who report cognitive problems that impact daily life and participation during the course of the disease,” Aicha Dijkshoorn, MSc, a neuroscientist and neuropsychologist at Utrecht University in the Netherlands, told Healio Primary Care. “In several cases, we indeed found cognitive impairments through neuropsychological assessments, which we were not able to comprehend fully based on current knowledge.”

For example, Dijkshoorn said, “we usually contributed cognitive impairments to chemotherapy, but we found several patients reported cognitive problems prior to treatment.”

To gain a better understanding, Dijkshoorn and colleagues conducted a systematic review of 17 studies with 1,978 adult patients who were placed in either a chemotherapy, radiotherapy and/or endocrine therapy or a healthy control cohort.

The researchers reported that the prevalence of cognitive impairment was 25% between cancer-related surgery and the initiation of chemotherapy, radiotherapy and/or endocrine therapy, 24% within 1 month of finishing cancer treatment and 21% at 1 year after treatment ended. These percentages were 10%, 10% and 7%, respectively, for healthy controls.

The researchers said chemotherapy appeared to influence cognitive dysfunction “more heavily” compared with endocrine therapy and/or radiotherapy (25% and 18% after treatment completion, 27% and 14% at 1-year follow-up, respectively). Some studies in the systematic review showed that, compared with their pretreatment level of cognitive functioning, 24% of patients experienced cognitive decline either after treatment or at 1‐year follow-up. Other studies reported that 15% of patients experienced cognitive improvement after treatment, whereas 31% of patients did so at the 1-year follow-up mark.

Dijkshoorn said that despite her clinical experiences, the prevalence of cognitive impairment in patients with breast cancer in the study was unexpected.

“The findings on the prevalence of cognitive impairments did surprise us, which made us realize that we must have missed it in a substantial number of patients,” she said. “In addition, the results shed new light on the course of cognitive impairments and that many patients suffer from cognitive impairments prior to treatment, suggesting that cognitive decline is not exclusively related to treatment such as chemotherapy.”

With cognitive decline observed in patients both before and after surgical treatments, risk factors that cancer and cognitive decline share (eg, genetic susceptibility, older age and lifestyle) could be responsible for the patients’ cognitive impairment, the researchers wrote. Another possible cause for the cognitive decline could be the growth of the cancer itself, according to Dijkshroon and colleagues.They wrote that other researchers “argue that peripheral cancers are associated with increased circulating inflammatory cytokines that can enter the blood stream and interface with the brain by passing the blood–brain barrier …. The constant production of cytokines will ultimately inflect pathological structural and biochemical changes in neuron populations central to cognitive function.”

According to Dijkshoorn, the study underscores the importance of evaluating patients’ cognitive function multiple times in their lifetimes.