Chemo Brain: A Decade of Evidence

Jeffrey S. Wefel, PhD; Alice Goodman, MA


November 01, 2013

In This Article

Chemotherapy Not the Sole Culprit

Medscape: Is there evidence that radiation causes chemo brain?

Dr. Wefel: It is well accepted and increasingly well understood that radiation directed at the brain has the potential to cause neurotoxicity. As a result, over the years radiation treatment plans have been adjusted to maximize the benefit of treatment and minimize toxicity by altering the dose of radiation, avoiding critical brain structures and exploring different types of radiation therapy.

Several recent trials have examined pharmacologic prophylaxis and alterations in the delivery of radiation to preserve cognitive function. For example, results of a double-blind, placebo-controlled clinical trial demonstrated that memantine was effective in preserving cognition in patients with brain metastases treated with whole-brain radiotherapy.[9]

Medscape: Do targeted therapies cause cognitive deficits?

Dr. Wefel: The jury is still out on the cognitive effects of many targeted therapies, but this is likely to be dependent on the specific pathway being targeted. For example, preclinical studies of erlotinib, an epidermal growth factor receptor inhibitor, suggest that this agent inhibits cancer cell lines but does not adversely affect progenitor stem cells.[10] A small clinical trial showed no additional neurotoxicity with erlotinib in patients with non-small cell lung cancer compared with patients not receiving erlotinib.[11]

However, the situation is more complicated. A number of targeted therapies interact with the VEGF pathway, which is important in normal brain development, neurogenesis, neuroprotection, and cognitive function, but the potential cognitive effects of anti-VEGF therapies have not been evaluated in human studies of cancer patients.


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