Biomarker could spot chemobrain early

Researchers may have discovered a biomarker for the cognitive impairment associated with cancer, called chemobrain.

Chemobrain can be subtle yet persistent, with some cancer patients reporting difficulties related to memory and attention even months after completing their treatment.

Given the extent of impact of chemobrain on patients, it will be useful if doctors could preemptively identify patients who are at higher risk of developing such symptoms with the use of a standardized, quantitative biomarker. They could then take the appropriate precautions to mitigate the side effects and help improve patients’ quality of life in the long run.

With this in mind, a team led by Alexandre Chan, an associate professor from National University of Singapore’s pharmacy department, started to investigate levels of biomarkers in relation to chemobrain, to better understand its cause.

“By identifying the clinically relevant factors which pre-dispose patients to chemobrain, more appropriate interventions can be tailored accordingly to patients who are at a higher risk of developing cognitive impairment,” explains Chan.

The team recently characterized plasma levels of the biomarker dehydroepiandrosterone (DHEA) and its sulfated form (DHEAS)—jointly referred to as DHEA(S)—to be biological determinants of chemobrain.

DHEA(S) are neurosteroids that help to regulate brain development, but researchers didn’t know previously whether their levels correlate with cognitive function or are associated with the onset of chemobrain.

The study showed that early-stage breast cancer patients with higher plasma DHEAS levels prior to chemotherapy had a lower risk of developing chemobrain in the specific domains of verbal fluency and mental acuity.

The researchers recruited 81 early-stage breast cancer patients who had no prior exposure to chemotherapy or radiotherapy and were going to receive chemotherapy treatment with curative intent. Researchers conducted the multicenter, prospective cohort study in the National Cancer Centre Singapore and KK Women’s and Children’s Hospital between 2011 and 2016.

To assess the extent of chemobrain, patients completed assessments for self-perceived and objective cognitive function before, during, and after chemotherapy. The validated questionnaire assessed patients on individual subdomains of mental acuity, concentration, memory, verbal fluency, functional interference, and multitasking. Conversely, researchers used the computerized neuropsychological test performed to assess processing speed, response time, memory, and attention of each patient. In addition, patients also completed a series of questionnaires to assess their fatigue symptoms, anxiety symptoms, and health-related quality of life.

Researchers quantified plasma samples they collected prior to chemotherapy for DHEA(S) levels.

“Our findings suggest that patients with higher prechemotherapy DHEAS levels had lower odds of developing self-perceived cognitive impairment. However, future studies are required to further investigate the effect of DHEA(S) on specific cognitive domains and to validate our findings in independent cohorts,” says first author Toh Yi Long, a doctoral student working with Chan.

Chan’s team is now exploring new research frontiers and looking at developing potential therapeutic interventions. These interventions may provide viable options to mitigate post-treatment complications (not limited to chemobrain) that cancer patients experience, with the overall goal to improve quality of life and to help restore normalcy in cancer survivors.

Source: National University of Singapore