What Could Cause Cognitive Dysfunction after Cancer?

Now that many researchers have accepted that some cancer patients experience cognitive dysfunction as a result of cancer and its treatment, they have begun trying to identify the mechanisms that might cause the problem.

Because cancer and its treatment are complex, and because the effects of both are varied, a specific cause may never be identified. Researchers have explored an array of possible culprits, including treatments that damage nerves, imbalances in the oxidative process, changes in hormones, dysfunction of the immune response, inflammation, secretion of immunomodulating cells (cytokines), changes in the brain’s connectivity and genetic predisposition. Studies have shown that post-traumatic stress disorder experienced by many cancer patients is also associated with cognitive dysfunction, making it difficult to discern how much could be treatment-related. The numbers are also inconsistent, with studies reporting 16 to 75 percent of patients saying they experienced cognitive dysfunction after cancer treatment.

Patricia Ganz, a professor of health policy and management at the Fielding School of Public Health and a professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles, found that use of chemotherapy was related to increased levels of soluble tumor necrosis factor receptor, an inflammatory marker associated with cancer-related fatigue in prior studies.

Ganz suggested fatigue, anxiety, depression and sleep disturbance were related to cognitive dysfunction and found correlations between self-reported cognitive complaints and greater levels of fatigue and depression among the participants in the study.

In an article published in Oncology Times, Ganz explained that “the increased cytokine levels traverse through the blood-brain barrier and likely cause local inflammation, which increases the levels of serotonin and dopamine in the brain that can cause depression, fatigue, and social withdrawal.”