Early treatment of slow-growing brain tumors may worsen cognitive function

The treatment of a slow-growing brain tumor is often accompanied by impaired cognitive functions such as difficulties with shifting focus and impaired language ability. This has been shown by a study managed by the University of Gothenburg. Researchers say that treatment early after diagnosis is not always optimal.

Slow-growing brain tumors, known as IDH mutated gliomas, have a relatively good prognosis. Treatment may include surgery, radiotherapy and chemotherapy.

However, the current study, published in the journal Neuro-Oncology, shows that many patients reveal measurable cognitive impairment in the first year after treatment. So far, these effects have not been thoroughly studied.

The research was conducted with patients at Sahlgrenska University Hospital in Gothenburg and Uppsala University Hospital. A total of 127 individuals were followed who underwent surgery and in most cases also radiotherapy and chemotherapy in line with current guidelines and treatment protocols. Participants underwent extensive testing of cognitive functions, both before surgery and one year after.

Poorer planning skills and language

The executive functions were most affected, i.e., the abilities needed to plan and organize one's life. In the study, the results were most evident regarding the ability to shift focus. Impairments in language functions, such as verbal speed, language learning and memory, were also common. The deterioration was most marked in participants who had received both radiotherapy and chemotherapy after surgery, and in the older population.

These functions are linked to the parts of the brain where slow-growing gliomas most frequently occur: in the frontal lobe, which manages behavior, personality, judgment and impulse control, and in the temporal lobe, which controls hearing, memory, language and emotions.

One of the leaders behind the study is Isabelle Rydén, a PhD student in clinical neuroscience at the University of Gothenburg and a Neuropsychologist at Sahlgrenska University Hospital.

Patients with IDH mutated gliomas generally live many years with their disease and we see that a high proportion have measurable changes in cognitive function already early after treatment. This underlines the importance of monitoring cognitive functions in the same way we monitor imaging and other medical parameters.”

Isabelle Rydén, PhD student in clinical neuroscience, University of Gothenburg

Risk of unnecessary functional impact

The researchers argue that the results show the need to consider cognitive consequences when discussing and planning treatment. Cancer treatment is central and in many cases crucial to prognosis but relying solely on the time frames of treatment protocols to guide decisions is not always optimal.

“It is not about forgoing treatment,” emphasizes Isabelle Rydén. “For some patients, starting intensive treatment early is an obvious choice. But for others, where the disease progresses more slowly, the therapeutic window is wider, posing an unnecessary risk of cognitive side effects if radiotherapy and chemotherapy are initiated too early”.

In the next step, the research team will investigate how patients' cognitive functions develop over time. The researchers plan to map factors that influence the course of the disease, as well as which areas and networks of the brain are especially sensitive to negative consequences of treatment.