Do Cancer and Its Treatment Affect Mental and Cognitive Functions?

Varying degrees of cognitive decline are common in people receiving chemotherapy; chemobrain is the name for this condition, which includes loss of attention, impaired concentration, working memory problems and impaired reasoning. Cognitive decline may be permanent or temporary. Although chemotherapy is among the first factors blamed for this problem in patients with cancer, a study by Dr. Tim A. Ahles and colleagues found that many factors affect cognitive function during this process.

According to the study by Dr. Ahles and colleagues, which examined neuropsychological status involving cognitive changes before and after treatment, brain imaging, genetic background and animal studies, age, hormone therapy (used alone or with chemotherapy), surgery, general anesthesia associated with surgery, radiation therapy, treatment dose and timing, and cancer itself were found to affect cognitive function.

In this case, calling cancer-related cognitive changes chemobrain may be an incorrect or incomplete description.

Hormone-suppressing medicines used to treat breast cancer, such as tamoxifen or anastrozole , change estrogen levels in the body rapidly and effectively. In some women, cognitive function may not be greatly affected by chemotherapy alone but may be affected by hormone therapy or by both together.

Another surprising finding in this field is that pretreatment assessments of people with breast cancer showed cognitive function lower than expected. This suggests a direct effect of cancer itself.

Genetic factors also affect cognitive function. For example, DNA repair mechanisms repair many genetic factors and damage. People with weak DNA repair mechanisms are more susceptible to developing cancer. Their likelihood of Alzheimer’s or Parkinson’s disease also increases. In other words, both cancer and diseases causing cognitive dysfunction may develop as a result of an underlying genetic disorder.

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Depression, stress, anxiety, and even sleep disorders and fatigue as physical factors also affect cognitive function. Considering previous studies, people receiving breast cancer treatment show cognitive impairment at widely varying rates of %17-75. One reason for such differences between studies is that some do not consider psychosocial conditions such as depression, worry and stress.

Most studies of cognitive function concern women and breast cancer. It is not entirely clear how far findings from these studies can be generalized to other cancer types and treatments. However, prostate cancer treatment involving testosterone hormone suppression (androgen ablation) is also thought to affect cognitive function. This is because testosterone is important for cognitive function in men, just as estrogen is in women. While estrogen influences verbal and written memory skills, testosterone is important for visual and spatial (3-dimensional) skills.

The Most Common Problems

Almost all patients complain of short-term memory loss. However, when we test their short-term memory, we observe that it is quite normal.

Highly educated people with greater cognitive reserve have also been found to be less affected by chemotherapy or trauma.

Sex Differences

Because most studies in this field focus on breast cancer, it is difficult to establish the precise percentage of men affected. However, some studies of lymphoma, leukemia and prostate cancer have observed effects on cognitive function in men as well.

Risk Assessment

Although we currently lack clear information on which individuals experience greater cognitive decline or how to prevent it, its mechanisms, who is at greater risk and how frequently it occurs are current research topics.

How Is Cancer-Related Cognitive Decline Treated?

Some studies have shown positive effects on improving memory, attention disorders and insomnia with modafinil . In addition, methylphenidate has been found effective for improving memory and increasing concentration. Online brain exercises have produced promising results in studies.

Studies using high-quality advanced imaging methods to observe changes in cognitive activity before and after treatment are continuing. Although there are no definitive clinical approaches today, it is hoped that developments capable of becoming part of clinical care will emerge in the future.