Study Suggests Common and Treatment-Specific Negative Effects on Cancer Survivor’s Cognitive Skills

A study published in the journal Cancer compares changes in cognitive function over a 3-year period among breast cancer survivors treated with radiation and chemotherapy to a noncancer control arm.

The study, “Cognitive Functioning After Cancer Treatment," (DOI: 10.1002/cncr.26432) shows that breast cancer survivors can experience problems with specific mental abilities up to several years after treatment. Similar results were seen in patients treated with radiotherapy alone or a combination of radiation and chemotherapy.

The study confirmed the link between chemotherapy and cognitive problems among breast cancer survivors. While the control noncancer group improved in processing speed over time, neither cancer cohorts improved and were found to have poorer executive functioning.

Paul Jacobsen, PhD, researcher at the Moffitt Cancer Center and colleagues, found that survivors who were treated with radiation had similar problems to those treated with a combination of radiation and chemotherapy.

The Study Cohort

Patients diagnosed with stage I or stage II breast cancer (62 treated with chemotherapy and radiotherapy and 67 treated with radiotherapy) and women with no history of cancer (184 subjects) completed neuropsychological assessments 6 months after treatment and 42 months after treatment. All patients were treated at the Moffitt Cancer Center or the University of Kentucky Chandler Medical Center. The noncancer subjects were matched to a cancer patient by age and geography. The vast majority of patients were white and well educated.

The neuropsychological tests used to assess cognitive function included the National Adult Reading Test, attention tests, executive functioning tests, nonverbal memory, processing speed, and verbal memory tests.

Since breast cancer survivorship is greatly improving, there is a need to understand the long-term effects of adjuvant treatment. Results of meta-analyses suggest that memory and concentration in breast cancer survivors suffers as a result of chemotherapy as measured by standardized neuropsychological tests. However, this is the first longitudinal study that assesses long-term cognitive function of survivors after treatment.

The current study results need to be confirmed on a larger cohort as the patients described here were highly homogenous. Additionally, the neurophysiological assessments do not always reflect the function of individuals in everyday life. Extension of this type of study to other, non–breast cancer survivors, longer-term follow-up and larger study cohorts will allow for more robust conclusions about cognitive impairment after cancer treatments.